bosch 5.2.1 engine management system
ENGINE MANAGEMENT
SYSTEMS
Student Workbook
TT19.3 Version 5.1
August 2006
©2006 LAND ROVER NORTH AMERICA, INC.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system,
or transmitted in any form without prior written permission from Land Rover North America, Inc.
CONTENTS
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
IGNITION SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
FUEL INJECTION SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
EMISSION CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
EVAPORATIVE EMISSION CONTROL SYSTEM (EVAP) . . . . . . . . . . . . . . . . . . . . . 47
ON-BOARD DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
LAND ROVER FUEL INJECTION SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
13/14CU AND 14CUX SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS) . . . . . . . . . . . . . . . . . . . . . . 107
GEMS CONNECTOR PINOUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
GEMS ECM TUNE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . 137
BOSCH ME 7.2 ENGINE MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . 227
DENSO ENGINE MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
CONTENTS
INTRODUCTION
INTRODUCTION
Overview
Modern engine management systems allow powertrain designers to maintain the critical
balance between performance, fuel economy, and emissions. As government regulations
concerning emissions and fuel economy become more demanding, the need for advanced fuel
delivery technologies and operational strategies that can meet these exacting standards
becomes greater.
Balancing Operating Priorities
To assist technicians servicing today's engine control systems, the Society of Automotive
Engineers (SAE) has developed standards that apply to all vehicle manufacturers. Topics
covered include diagnostic trouble codes (Standard J2012) diagnostic connector form and
location (J1962) and even automotive terms and acronyms (J1930). These terms and
standards, used throughout this book, can help build a bridge between your knowledge of basic
vehicle operating systems and specific Land Rover applications.
Introduction
1
INTRODUCTION
THEORY
It has long been known that the key to efficient combustion is maintaining the proper
relationship between air and fuel. The point at which fuel burns most efficiently is known as the
stoichiometric ratio. With gasoline engines, the stoichiometric ratio is approximately 14.7 (air)
to 1 (fuel). Keeping this relationship constant is a challenge, as the engine must operate under
continually changing conditions and loads.
Stoichiometric Ratio
Once the stoichiometric ratio has been achieved, igniting the air/fuel mixture at the appropriate
time presents the next big challenge. Although it seems to occur instantaneously, combustion
takes time.
And while combustion time remains relatively constant, the environment in which it occurs (an
automotive cylinder with a moving piston) changes dramatically depending on engine speed.
The appropriate spark timing at idle will not be the most effective point of ignition at 4,000 rpm.
The key is not to compromise, but to provide the best point of ignition for every operating
condition.
A modern engine needs a system to manage the complex collection of inputs and outputs and
correctly interpret the ways they relate to each other. This course is about the sophisticated
systems that have been developed to control the supply of air and fuel, and to control the exact
moment at which this mixture is ignited.
Incorrect application of any of these three inputs (air/fuel/ignition) can lead to unsatisfactory
performance, poor fuel economy, and/or excessive exhaust emissions.
2
IGNITION SYSTEMS
IGNITION SYSTEMS
Introduction
Providing the proper air/fuel mixture is an important factor in promoting efficient engine
operation. However, once the air/fuel mixture is introduced into the cylinder, it must be burned
efficiently. The combustion process on a gasoline engine can't begin until a spark is introduced.
Accurate timing of the spark in relation to piston position and can provide the difference
between peak performance and inefficient operation.
When a spark is introduced to the air/fuel mixture in the cylinder, a flame front is generated.
With proper ignition timing, the flame front exerts force on the piston just as it begins its
downward movement. To allow time for the force to reach the piston, ignition occurs before the
piston reaches Top Dead Center (TDC). However, if ignition occurs too soon, the force of
combustion contacts the piston on its way up. This produces engine knock. If ignition takes
place too late, engine performance lags.
The natural rotation of the crankshaft keeps the piston at or near TDC for approximately 46° of
its rotation (23° Before TDC to 23° After TDC). The crankshaft rotates at a constant speed, but
the piston moves very little at this point. Once past 23° ATDC, the piston begins to move very
rapidly. For best results, the burn should be completed as close to 23° ATDC as possible.
Piston Position at Top of Stroke
Ignition Systems
3
IGNITION SYSTEMS
As engine speed increases, spark must be further ahead of TDC to allow adequate time for the
air/fuel mixture to burn completely. Because of this, increasingly sophisticated methods of
advancing and retarding ignition have been implemented.
Spark Timing Window
The high voltage required for ignition is generated in the vehicle's ignition coil. It contains two
sets of windings, primary and secondary, that allow battery voltage to be stepped up to
approximately 30,000 volts.
Ignition Coil
4
IGNITION SYSTEMS
ELECTRONIC IGNITION SYSTEMS
Early electronic ignition systems used a single coil with a distributor to fire the cylinders in the
correct sequence. The spark was triggered by a pickup within the distributor. The main timing
control was a mechanical advance geared to the crankshaft rotational speed, additional
advance at part throttle was provided by a vacuum servo mounted on the distributor body.
A sensor (pickup) mounted in the distributor generates pulses as a trigger wheel mounted to the
distributor shaft passes it. Later models have the ignition control module mounted to the ignition
coil bracket.
Land Rover vehicles discontinued use of this system in 1996.
Solid State Ignition System
Ignition Systems
5
IGNITION SYSTEMS
Two methods are used to advance ignition timing. A centrifugal mechanism mounted internally
in the distributor advances timing as rotational speed of the engine (and distributor shaft)
increases.
A vacuum advance mechanism is mounted externally on the distributor body. This helps provide
advance over and above that provided by the centrifugal mechanism when operating at part
throttle.
Distributor
6
IGNITION SYSTEMS
DIRECT IGNITION SYSTEM
To more accurately control engine operation and emissions, most modern systems use a Direct
Ignition System (DIS). The ignition system is controlled by the Engine Control Module (ECM)
which receives inputs from a variety of sensors. This information is then processed to provide
the optimum spark advance for every operating condition.
Engine Control Module
Typical ECM Ignition Control Map
Ignition Systems
7
IGNITION SYSTEMS
INPUTS
Crankshaft Position Sensor (CPS)
Basic engine timing is controlled by the ECM using input from the crankshaft position sensor. It
is mounted on the flywheel housing, opposite the starter motor.
Crankshaft Position Sensor
The sensor reacts to reluctor teeth placed on the flywheel at precise intervals, with some means
of identifying the TDC position of the #1 piston. In the example pattern shown, the teeth are
spaced at 10º intervals, and one missing reluctor tooth identifies the T.D.C. position of the #1
piston. The electrical signal produced by the crankshaft position sensor as the teeth pass it
provides a constant update of engine speed and crankshaft position to the ECM.
Typical Crankshaft Position Sensor Signal
8
IGNITION SYSTEMS
Engine Coolant Temperature Sensor
Variations in engine operating temperature require variations in ignition timing to maintain the
optimum balance between driveability and emissions. The ECM advances ignition timing when
the engine is cold and retards it as the engine warms up. The coolant temperature sensor
provides the ECM with data on which to base these timing decisions.
Coolant Temperature Sensor
Knock Sensors
A pair of knock sensors monitors engine noise and vibration for the ECM. Engine knock is often
caused by detonation or pre-ignition which can damage pistons and valves. The ECM is able to
identify the characteristics of engine knock and retard ignition timing when knock is present.
The ability to sense engine knock allows the ECM to operate the engine close to its limits of
ignition advance. This is the most efficient ignition timing for maximum performance and fuel
economy.
Knock Sensor
The sensors are mounted in the cylinder block located between cylinders 3 and 5 and between
cylinders 4 and 6. Positioning a sensor in each bank of cylinders allows the ECM to precisely
identify which of the eight cylinders is knocking.
Ignition Systems
9
IGNITION SYSTEMS
OUTPUTS
Coils
Spark distribution is achieved by a pack of coils mounted at the rear of the engine compartment.
Coil operation is controlled by the ECM. A single coil is used to fire two plugs simultaneously one on the compression stroke and the other on the exhaust stroke. The circuit for each coil is
completed by switching within the ECM.
The spark on the exhaust stroke is said to be wasted hence, the term “wasted” or “lost” spark
ignition system. Actually, little in the way of voltage is wasted on the spark in the cylinder on the
exhaust stroke. The cylinder containing the air/fuel mixture (compression stroke) conducts the
electrical charge far more efficiently than the cylinder containing exhaust gasses. Most of the
voltage takes this path of least resistance to ground.
Performance is also improved. By using more than one coil (as opposed to the traditional single
coil system) each coil is allowed more time to charge between firings.
Other DI systems may use a separate coil for each cylinder, mounted directly on the plug (COP)
or connected via a short high voltage lead. Each coil is controlled directly by the ECM.
Multiple Ignition Coil Packs- Bosch (left), GEMS (right)
Coil On Plug
10
FUEL INJECTION SYSTEMS
FUEL INJECTION SYSTEMS
Recent years have seen the process of automotive fuel delivery evolve from carburetors to fuel
injection. Current Land Rover vehicles use one of two types of electronically controlled fuel
injection systems: Multiport Fuel Injection (MFI) or Sequential Multiport Fuel Injection (SMPI).
MULTIPORT FUEL INJECTION (MFI)
Multiport fuel injection systems utilize an injector for each engine cylinder. These injectors are
mounted above the cylinder's intake valve in the intake manifold. The injectors for each bank of
cylinders open twice during the four-stroke engine cycle - once each during the intake and
exhaust strokes.
Since the injectors spray fuel into the manifold on the back face of each intake valve, there is no
need for injection to be precisely timed to valve operation or combustion stroke.
Fuel is injected twice per stroke because two small portions of fuel are more easily atomized
than a single large quantity. The atomized fuel is then drawn into the cylinder intake for
combustion. MFI allows for precise fuel control for each bank of cylinders.
Multiport Fuel Injection
Fuel Injection Systems
11
FUEL INJECTION SYSTEMS
SEQUENTIAL MULTIPORT FUEL INJECTION (SFI)
Sequential multiport injection goes a step further in fuel delivery precision. By providing
separate ECM ground controls for each injector, SFI provides control of individual injectors.
This differs from MFI systems which control operation of the injector banks.
The SFI system allows the supply of fuel to be matched to the specific needs of each individual
cylinder. It also requires that injector operation be precisely timed to valve operation. The ECM
in an SFI system uses additional inputs, over and above those found in an MFI system, to
control injector operation.
Because an equal amount of fuel is injected into each cylinder, engines equipped with port fuel
injection systems must ensure that equal amounts of air enter each cylinder. This is achieved by
providing equal length intake tracts connected to a common chamber or plenum.
Sequential Multiport Fuel Injection
12
FUEL INJECTION SYSTEMS
FUEL SYSTEM COMPONENTS
The following components are included in a basic fuel injection system:
•
•
•
•
•
•
Engine Control Module (ECM)
Oxygen Sensor (HO2S)
Fuel Pump
Fuel Filter
Fuel Pressure Regulator
Fuel Injectors
Additional components are used to monitor and control the “air” portion of the air/fuel mixture.
These are listed below:
•
•
•
•
Mass Air Flow Sensor (MAFS)
Throttle Butterfly
Throttle Position Sensor (TPS)
Idle Air Control (IAC)
Basic Fuel Injection System
Fuel Injection Systems
13
FUEL INJECTION SYSTEMS
Engine Control Module (ECM)
The Engine Control Module (ECM) is the heart of the vehicle's fuel delivery system. It monitors
information from several inputs to determine the fuel delivery strategy required to produce
efficient operation. As the sophistication of the fuel injection system increases, the amount of
information processed by the ECM also increases. Additional strategies to cover fueling
requirements for situations such as cold starting, hot starting, and wide-open throttle
acceleration may also be added to the ECM software.
Newer generations of engine management systems include additional ECM memory to allow
such features as adaptive sensor mapping strategies, cylinder knock control, active ignition
timing, and extended fault diagnostics.
Engine Control Module (ECM)
14
FUEL INJECTION SYSTEMS
FUEL SYSTEM OUTPUTS
Fuel Pump
Fuel is supplied to the engine via a tank-mounted electric pump. In the case of a system that
uses an external fuel filter, an additional filter may also be used on the pump inlet to protect the
fuel pump itself.
The pump is usually mounted inside the fuel tank. The advantage of mounting the pump in the
fuel tank is that the pump armature and bearings are cooled by the surrounding fuel. The tank
also helps isolate any noise produced by pump operation. The pump is capable of delivering
more fuel volume and pressure than required by the engine. A non-return valve in the pump
prevents fuel from the injector supply pipe from draining back into the tank when the pump is not
running.
There are two general types of fuel supply strategies in use- the Fuel Return type, and the NonReturn type.
In the return type, most of the fuel circulates through the fuel rail and is returned to the fuel tank.
This constant supply of relatively cool fuel through the system helps prevent vapor lock. This
type of system uses a pressure regulator mounted on or near the fuel rail. The regulator senses
engine manifold pressure and adjusts the quantity of fuel returned to the fuel tank. On the fuel
pump itself, there is a pressure relief valve to prevent over-pressure in the event of a system
blockage.
In the Non-Return type, the fuel rail has no means to return fuel to the tank. In this type of
system the pressure at the fuel rail is typically higher than in the return type system, and
regulation is integral with the pump. Excess fuel can be returned to the tank, but it is done via
the relief valve inside the pump.
Fuel Pump
Fuel Injection Systems
15
FUEL INJECTION SYSTEMS
Fuel Filter
Because of the close internal tolerances of the injectors, thorough filtration of fuel is required.
The filter element is able to trap particles down to 20 microns in size.
Fuel Filter
Most modern engine management systems use a filter that is mounted on the fuel pump, and
inside the fuel tank. Some systems however (typically the Return type), use an externally
mounted filter.
The fuel filter is a simple component that is commonly overlooked as a source of fuel system
concerns. Check for proper system pressure at the fuel rail before disassembling the fuel rail or
injectors in search of an obstruction.
16
FUEL INJECTION SYSTEMS
Fuel Pressure Regulator
A constant pressure to the fuel injectors must be maintained during all engine operating
conditions to ensure correct fuel metering and emission levels. As previously mentioned, return
type systems use an external regulator, while non-return type systems use a regulator mounted
inside the fuel tank, on the fuel pump.
Non-return type Systems
This type of fuel pressure regulator is located in the fuel pump assembly, and maintains a
constant fuel pressure relative to atmospheric pressure. The supply pressure at each injector
must be sufficient to provide adequate fuel flow during high demand such as acceleration under
load, and wide open throttle. There must also be sufficient pressure to keep the injectors seated
during periods of high intake vaccum, such as during deceleration.
Since fuel pressure is regulated well before the fuel rail assembly, proper engine fuelling with
this type of supply system is slightly more sensitive to restrictions in the supply pipes than in a
return type system. Typically, a fuel pressure test port is provided on the fuel rail to verify
adequate pressure at the injectors.
Typical Non-Return Type System Pressure Regulator
Return type systems
A constant fuel pressure relative to, and above intake manifold pressure, is controlled by a
regulator valve mounted at the end of the fuel injector rail. The fuel pressure regulator contains
two chambers separated by a spring-loaded diaphragm. One chamber contains fuel from the
supply line. The other chamber is linked to the engine side of the throttle butterfly to sense
manifold vacuum (negative pressure).
Fuel Injection Systems
17
FUEL INJECTION SYSTEMS
When fuel pressure and manifold vacuum are low (full throttle), spring pressure holds the
diaphragm valve against the fuel return pipe. This assures a higher level of fuel pressure to
satisfy the fuel needs of the injectors. Fuel pressure must exceed a calibrated amount before
the spring is compressed and fuel is allowed to enter the return line.
Regulator Closed
When manifold vacuum is high (idle and coast-down), the combination of fuel pressure and
vacuum is able to overcome the pressure of the regulator spring. The fuel return line opens at
much lower fuel pressures when vacuum assist is present. This reduces the tendency of
manifold vacuum to draw excess fuel from the injector nozzle and ensures that the amount of
fuel actually delivered matches the level desired by the ECM.
The fuel pressure regulator is pre-set during manufacture. No service adjustments are
provided.
Regulator Open
18
FUEL INJECTION SYSTEMS
Fuel Injectors
The electronically operated fuel injector provides a simple and effective way of metering the fuel
provided for combustion.
Fuel Injection Systems
19
FUEL INJECTION SYSTEMS
Each injector contains a precisely machined needle valve or a pintle and sealing valve held in
position by a spring. When the injector solenoid is energized, the needle or pintle is lifted,
allowing fuel to pass. When the solenoid is de-energized, the needle or pintle snaps shut under
spring pressure, cutting off fuel flow.
Fuel Injector Types
The length of time the injector is energized and delivering fuel is referred to as injector "pulse
width." This varies between 1.5 to 10 milliseconds, depending on operating conditions. The
longer the injector is energized, the greater the volume of fuel delivered. The ECM uses the
duration of its ON signal to the injector (where it provides a ground for the circuit) to control fuel
delivery to the cylinder.
Injector Pulse Width
When looking at injector operation using an oscilloscope, an additional ‘spike’ will be observed
20
FUEL INJECTION SYSTEMS
along with the ‘on-time’, or pulse width. This spike is the result of voltage build-up, current flow
and limiting, and collapse in the injector solenoid winding.
To further enhance the combustion process, the tip of the injector's needle valve is precision
ground to a shape that produces a fine atomized fuel spray. This enables the fuel to vaporize
faster and more completely than fuel introduced by a carburetor. The result is more complete
and efficient combustion.
Atomized Fuel
As long as the supply of fuel to the injector is sufficient, the volume of fuel delivered can be
precisely controlled by the length of time the injector needle valve is open. The valve remains
open as long as a path to ground is provided by the ECM.
Fuel Injection Systems
21
FUEL INJECTION SYSTEMS
Idle Air Control (IAC)
To ensure a smooth and constant idle speed, a port allows a measured amount of air to bypass
the throttle plate and enter the plenum chamber. Generally the system allows this bypass when
the following conditions are present:
• Low or No road speed
• Throttle closed
• Engine above cranking speed rpm
The amount of air flowing through an orifice is controlled by the ECM. This orifice and its control
mechanism is called an Idle Air Control Valve (IACV). The IACV can be a tapered valve
mounted in the by-pass port, or a slotted disc or drum rotating into the bypass air flow. In either
case, the precise movement of this variable restriction is controlled by the ECM, usually using
an electric motor.
NOTE: Electronic throttle control systems do not use an IACV as they are able to control the
throttle plate directly.
The ECM makes idle air control adjustments based on sensor inputs (ambient temperature,
engine load produced by accessories such as air conditioning or defrosters) to keep idle speed
sufficient for the situation.
If a tapered valve type of IACV is used, the motor uses multiple windings that are powered in
sequence to allow small ‘steps’ of motor movement. Thus, this type of motor is called a ‘stepper’
motor.
If a disc or drum type of IACV is used, the position of the disc or drum is controlled by a motor
with two opposing windings. The power to the windings is alternated between the two by
varying the amount of time each recieves current. In this way, the disc or drum can be precisely
positioned.
Failure of the stepper motor can result in either a high or low idle speed, engine stall or no-start.
22
FUEL INJECTION SYSTEMS
“Base” idle is controlled through a separate bypass port located in the housing for the throttle
butterfly. The volume of air allowed to bypass the throttle butterfly is controlled by an adjustment
screw. The size of this orifice does not vary during engine operation.
Stepper type Idle Air Control
Fuel Injection Systems
23
FUEL INJECTION SYSTEMS
FUEL SYSTEM INPUTS
Heated Oxygen Sensor (HO2S)
The oxygen (Lambda) sensor mounted in the exhaust downpipe serves as the key input in an
electronic fuel injection system. The sensor is used by the ECM to determine the amount of
oxygen present in the exhaust gas. The ECM uses this information to increase or decrease
injector open time to bring the air/fuel ratio as close to Stoichiometric as possible.
Heated Oxygen Sensor
Oxygen sensors operate efficiently only when warm. Sensors include heaters to help them
reach operating temperatures quickly. This allows the sensors to provide accurate information
to the ECM soon after start-up and allows the system to enter closed loop operation (based on
sensor inputs) sooner. Closed loop operation helps provide an efficient fuel mixture and
controls emissions when the engine is cold. Closed loop also guards against catalytic converter
overheating from the introduction of too much fuel.
“Closed loop” simply means that the ECM is controlling fuel to the engine based on the oxygen
sensor “feedback”, rather than using a programmed mixture based solely on engine
temperature, speed, and load. Closed loop operation helps provide an efficient fuel mixture and
controls emissions when the engine is cold. Closed loop also guards against catalytic converter
overheating from the introduction of too much fuel.
There are three general types of Oxygen Sensors:
• Those that change resistance in the presence of oxygen in the exhaust
• Those that generate a voltage based on the absence of oxygen in the exhaust
• “Wide Band” sensors that change a current flow signal in a reference circuit, based on the
air/fuel content of the exhaust gas. These are also sometimes referred to as “Air/Fuel ratio”,
or A/F sensors
The first two types of oxygen sensors are referred to as “Heated Exhaust Gas Oxygen-Sensor”
(HEGO) and their signals are continually "switching" between rich and lean as the exhaust gas
content changes. The engine management system is programmed to understand that a
stoichiometric air/fuel ratio is roughly mid-way between the low and high signal values from the
sensor, and constantly corrects the fuel mixture to maintain an average mid-point reading.
It is best to measure HEGO operation through the ECM with a diagnostic tester, although it is
possible to measure them directly at the sensor or wire harness connections.
24
FUEL INJECTION SYSTEMS
“Wide Band” sensors are referred to as “Universal Heated Exhaust Gas Oxygen-Sensor”
(UHEGO) and are able to provide the system with a much more accurate air/fuel ratio reading.
Their signals change in direct proportion to the changes in air/fuel ratio, and consequently
change more slowly. The signals from these sensors cannot be easilly measured at the sensor,
and must be measured through the ECM via a diagnostic tester such as T4/WDS.
Typical HEGO sensor operating ranges
Typical “Wide Band” or UHEGO sensor operating range
On systems with more than one sensor, the ECM monitors each sensor separately. Fuel trim
adjustments are made independently to each cylinder bank, or individual cylinder, depending on
the fuel system. Sensors located downstream of the catalyst are used to verify proper catalytic
converter operation.
Fuel Injection Systems
25
FUEL INJECTION SYSTEMS
In their operating environment, oxygen sensors are quite durable. However, they are easily
damaged if dropped, exposed to excessive heat, or contaminated. Care should be taken when
handling oxygen sensors. Avoid overtightenig or jarring the sensor. Contamination of the
sensor body can lead to premature failure. The sensor threads must be sealed with the
material provided to ensure there are no oxygen leaks. Do not use silicone sealants for this
purpose as they will contaminate the sensor.
Mass Air Flow Sensor (MAFS)
The Mass Air Flow Sensor (MAFS) is an electronic device mounted between the air filter and
the plenum chamber. It serves as a key ECM input, performing two functions: indicating the
volume and temperature of air being drawn into the engine. These two factors allow the ECM to
adjust the fuel supply accordingly.
Air density varies with temperature and altitude. Cold air is denser and contains more of the
oxygen required for combustion. At higher temperatures and altitudes, more air must enter the
engine to deliver the same amount of oxygen.
Air Density
The “Hot Wire” type of MAF sensor contains two wires with current passing through them. Both
are connected to the module mounted on the MAF unit. One wire, which is unheated, reacts to
intake air temperature. The second wire is heated to a known fixed temperature value above
the unheated wire. As air flow increases, the current required to maintain this difference in
temperature increases. The electronic module monitors this wire's current requirements to
determine the amount of air entering the intake manifold. It then provides a signal to the ECM
that corresponds to the air flow. While air temperature is also a factor that affects the current
requirements of the wire, a separate sensor for air temperature is commonly used.
26
FUEL INJECTION SYSTEMS
Another type of MAF sensor contains two elements made of a film material, that behave similar
to the wires in the hot-wire type.
Mass Air Flow Sensor
Throttle Butterfly
The throttle butterfly is located between the plenum chamber and the MAF sensor. The throttle
butterfly controls the volume of air entering the plenum chamber and is either linked directly to
the accelerator pedal or is controlled by the ECM via a motor. As the accelerator pedal is
depressed, the throttle butterfly opens. This allows a greater volume of air to enter the plenum
chamber.
Throttle Position Sensor (TPS)
A potentiometer mounted at the throttle butterfly converts throttle position into an electrical
signal used by the ECM (along with data from the air flow meter) to determine the volume of air
entering the intake manifold.
Fuel Injection Systems
27
FUEL INJECTION SYSTEMS
The ECM also monitors the throttle position sensor for the rate of throttle application. During
periods of hard acceleration, the ECM will enhance the fuel mixture to prevent a lag in engine
response.
Throttle Position Sensor
Electronic throttles (“drive by wire” systems) use 2 potentiometers. One potentiometer is
mounted on the throttle pedal, and monitors driver demand. The second potentiometer is
mounted at the throttle butterfly to monitor the actual butterfly position.
Electronic throttle systems provide the ECM with accurate and consistent feedback of the
throttle position and allow the system to adapt to variations caused by throttle stop wear and
component differences. These ECM adaptions must be reset if throttle components are
replaced of disturbed.
28
FUEL INJECTION SYSTEMS
CLOSED LOOP OPERATION
During closed loop, or feedback operation, the ECM controls fuel system operation based on
information provided by the various vehicle inputs. Because these inputs represent actual
operating conditions, the system is most able to meet performance and efficiency targets when
operating in closed loop.
The primary input during closed loop operation is the oxygen sensor since it indicates the result
of the combustion process, regardless of the engine speed and load.
The primary output during closed loop operation is the fuel injector timing and duration.
All other sensors generally serve to help the ECM ‘trim’ or anticipate the operation of the engine
to meet a particular oxygen sensor value or known tailpipe emission condition.
Fuel Injection Systems
29
FUEL INJECTION SYSTEMS
OPEN LOOP OPERATION
At times (start-up, full throttle) engine operating requirements may fall outside the bounds of
that suggested by the ECM inputs. Some sensors do not operate at peak efficiently until warm.
At these times, the ECM substitutes a pre-programmed set of reference inputs that are most
likely to produce desired engine operation. This is referred to as open loop operation.
The system may also default to open loop operation when component failure provides an input
signal outside the range of known parameters recognized by the ECM. The ECM will substitute
a signal value that allows the vehicle to continue to operate. The Malfunction Indicator Lamp
(CHECK ENGINE) on the instrument panel is illuminated at this time to indicate the failure of an
emissions-related component.
30
EMISSION CONTROLS
EMISSION CONTROLS
Introduction
Emissions control systems on Land Rover vehicles work closely with fuel system controls to
reduce airborne pollutants. Improper operation of these systems can lead to increased
emissions and poor engine performance. The catalytic converter is used to clean up tailpipe
emissions. Crankcase ventilation and evaporative purge address a different concern - the
evaporative emissions produced by the vehicle.
CATALYTIC CONVERTER
Even when operating at peak efficiency, engines produce undesirable emissions as a result of
the combustion process. A three-way catalytic converter, located in the vehicle's exhaust
system, is able to reduce the three greatest sources of concern - Hydrocarbons (HC) Carbon
Monoxide (CO) and a variety of Nitrous Oxides (NOx) - from tailpipe emissions.
To operate properly, a catalytic converter must reach very high temperatures (approximately
760° C or 1400° F). That is why it is mounted directly downstream from the exhaust manifold
Catalytic Converter
Exhaust gasses pass through and heat the converter core which contains a mixture of platinum
and rhodium. The combination of materials in the core and extreme temperature promotes
chemical reactions that reduce the HC, CO and NOx to harmless Carbon Dioxide (CO2)
Nitrogen (N2) and water (H2O). (Three way catalyst.)
Precise control of the air/fuel ratio is critical for effective catalyst operation. The chart below
shows that once the mixture moves away from stoichiometric, catalyst efficiency suffers.
Emission Controls
31
EMISSION CONTROLS
The two greatest enemies of catalyst life are leaded fuels and overheating. The use of leaded
fuels will cause deposits to form in the converter core and reduce its ability to produce the
desired chemical reactions.
Excessive core temperatures are produced during misfire situations when raw gas in the
exhaust ignites in the catalyst core. This can cause the core to fuse into a solid mass that
exhaust gasses cannot pass through. Because of this, the desired chemical reactions cannot
take place. Poor engine performance due to high backpressure is often a result of this situation.
Catalyst Operating Efficiency
CRANKCASE VENTILATION
During engine operation, noxious gasses are produced in the engine's crankcase. The
crankcase ventilation system allows these gasses to be burned along with the air/fuel mixture.
As an additional source of air to the engine's plenum chamber, the crankcase ventilation system
could be considered an integral part the vehicle's air intake system.
Manifold vacuum (negative pressure) draws oil laden vapor in the crankcase through an oil
separator on the valve cover. The separator prevents engine oil from being drawn into the
plenum.
The remaining gasses flow through a line where they are mixed with fresh air and directed to
the plenum. Here the gasses become part of the air/fuel mixture and are burned during normal
engine combustion.
32
EMISSION CONTROLS
The air intake on the valve cover of the opposing cylinder head prevents excessive crankcase
vacuum or pressure from developing during engine operation. It is fitted with a filter to prevent
contaminants from entering the crankcase. On some models, the filter has been replaced by a
hose supplying air that has already passed through the engine's air filter.
Crankcase Ventilation
Emission Controls
33
EMISSION CONTROLS
Evaporative Emission Control System (EVAP)
EVAPORATIVE PURGE
As gasoline from the fuel tank is pumped to the engine, air must enter the system to prevent a
vacuum from developing. However, harmful hydrocarbon vapors form in the fuel tank as
gasoline evaporates. Venting the fuel tank directly to the atmosphere would allow these vapors
to escape.
To prevent this from occurring, fuel system vapors are routed to a charcoal canister which
absorbs and stores fuel vapor from the tank when the engine is not running. Once the engine is
started, the vapor is purged from the canister by fresh air drawn through an orifice at the base of
the canister and the vacuum introduced at the top.
Evaporative Purge System Components
On 1989 and later vehicles, purge operation is controlled by the ECM through a solenoid valve.
When the valve is opened, the vapor is drawn into the plenum to be added to the air/fuel
mixture. Control of evaporative purge operation is an important ECM function for effective
emission control.
When operating, purge flow into the plenum is not accounted for in the ECM's air/fuel
calculations. Because of this, purge operation is saved for those times when the additional
vapor is least likely to affect emissions. Typically, this is when the engine is warm and operating
well above idle speed.
34
EMISSION CONTROLS
The ECM controls the flow rate by opening, closing, or pulsing the solenoid valve. The ECM
monitors purge flow by looking for signs from the oxygen sensors that the fuel mixture has been
enriched when the solenoid valve is opened. When this no longer occurs, the ECM interprets
this to mean that no more vapor is present. Purge operation is discontinued at this time.
Emission Controls
35
EMISSION CONTROLS
It is important that purge occur only as long as vapor is present. This reduces the time period in
which unmetered air is introduced into the plenum. A purge solenoid stuck in the open position
will increase vehicle emissions and affect driveability, especially at idle.
Purge Operation
EVAP With Leak Detection
OBDII Legislation requires that the ECM must indicate the occurrence of a fault to the driver, if a
leak in the fuel system allows hydrocarbons to escape to atmosphere. It will do this whenever it
detects leakage greater than a predetermined rate. This rate was initially based upon the
amount permitted to escape through a 1 mm (0. 04”) diameter hole, and for later models, a
0.5mm (0.02”) diameter hole.
36
EMISSION CONTROLS
1
Purge valve
8
Anti-trickle valve
9
Liquid vapor separator
2
Service port
3
Canister Vent Solenoid (CVS)
unit
10
Fuel filler cap
4
Filler neck
11
Roll over valves (ROV's)
5
Charcoal canister breather tube
12
Fuel tank assembly
6
Vent pipe to charcoal canister
13
Charcoal canister
7
Pipe connection to OBD sensor
in fuel pump
14
Purge line connection to engine
manifold
The ECM uses the purge system and a fuel tank pressure sensor to check the integrity of the
fuel system. The ECM purges the charcoal canister of vapor and then closes the charcoal
canister vent valve. This action produces a vacuum within the fuel tank. At a predetermined
vacuum, the purge valve is closed. This action seals the fuel system. The ECM then monitors
the rate at which the pressure within the fuel tank climbs to atmospheric pressure. The rate at
which the pressure equalises is assessed against a ‘model’ (i.e. a pre-programmed map) of fuel
evaporation. If a leak exists, then the pressure will equalize rapidly.
Emission Controls
37
EMISSION CONTROLS
The ECM completes the purge test only while the vehicle is stationary and the engine is at idle.
The test compensates for the natural evaporation of gasoline, which occurs when it is exposed
to a slight vacuum. If any condition is detected that would produce an excessive level of natural
evaporation levels (e.g. excessive air temperatures or a large degree of movement of fuel within
the fuel tank), the diagnostic is cancelled.
Canister Vent Solenoid Assy.
Purge Control Valve
38
EMISSION CONTROLS
If the ECM detects a leak in the fuel system (i.e. it has an air leak greater than 1 mm (0. 04”) in
it), it will record a fault code. A loose fuel filler cap can cause the ECM to incorrectly diagnose
an excessive air leak, so always ensure that the fuel filler cap is tight if the ECM has logged a
present fault with the EVAP system. If the ECM records a fault code, the engine speed, engine
coolant temperature and battery voltage is also recorded when the fault is first recognized. If the
ECM detects a fault within the EVAP system on two consecutive ‘journeys’, then it will illuminate
the MIL lamp.
Fuel Tank Pressure Sensor
Emission Controls
39
EMISSION CONTROLS
Secondary Air Injection (SAI)
The secondary air injection system is used to limit the emission of carbon monoxide (CO) and
hydrocarbons (HCs) that are prevalent in the exhaust during cold starting of a spark ignition
engine. The concentration of hydrocarbons experienced during cold starting at low
temperatures are particularly high until the engine and catalytic converter reach normal
operating temperature. The lower the cold start temperature, the greater the prevalence of
hydrocarbons emitted from the engine.
There are several reasons for the increase of HC emissions at low cold start temperatures,
including the tendency for fuel to be deposited on the cylinder walls, which is then displaced
during the piston cycle and expunged during the exhaust stroke. As the engine warms up
through operation, the cylinder walls no longer retain a film of fuel and most of the hydrocarbons
will be burned off during the combustion process.
The secondary air injection (SAI) system uses the following components:
•
•
•
•
•
•
Secondary air injection pump
SAI vacuum solenoid valve
SAI control valves (2 valves, 1 for each bank of cylinders)
SAI pump relay
Vacuum reservoir
Vacuum harness and pipes
The SAI pump is used to provide a supply of air into the exhaust ports in the cylinder head, onto
the back of the exhaust valves, during the cold start period. The hot unburned fuel particles
leaving the combustion chamber mix with the air injected into the exhaust ports and
immediately combust. This subsequent combustion of the unburned and partially burned CO
and HC particles help to reduce the emission of these pollutants from the exhaust system. The
additional heat generated in the exhaust manifold also provides rapid heating of the exhaust
system catalytic converters. The additional oxygen which is delivered to the catalytic converters
also generate an exothermic reaction which causes the catalytic converters to ’light off’ quickly.
The catalytic converters only start to provide effective treatment of emission pollutants when
they reach an operating temperature of approximately 250° C (482° F) and need to be between
temperatures of 400° C (752° F) and 800° C (1472º F) for optimum efficiency. Consequently, the
heat produced by the secondary air injection “afterburning”, reduces the time delay before the
catalysts reach an efficient operating temperature.
The engine control module (ECM) checks the engine coolant temperature when the engine is
started, and if it is below 55° C (131° F), the SAI pump is started. Secondary air injection will
remain operational for a period controlled by the ECM and is dependent on the starting
temperature of the engine. This varies from approximately 95 seconds for a start temperature of
8° C (46° F) to 30 seconds for a start temperature of 55° C (131° F). The SAI pump operation
can be cut short due to excessive engine speed or load.
Air from the SAI pump is supplied to the SAI control valves via pipe work and an intermediate Tpiece which splits the air flow evenly to each bank.
40
EMISSION CONTROLS
At the same time the secondary air pump is started, the ECM operates a SAI vacuum solenoid
valve, which opens to allow vacuum from the reservoir to be applied to the vacuum operated
SAI control valves on each side of the engine.
When the vacuum is applied to the SAI control valves, they open simultaneously to allow the air
from the SAI pump through to the exhaust ports. Secondary air is injected into the inner most
exhaust ports on each bank.
When the ECM breaks the ground circuit to de-energize the SAI vacuum solenoid valve, the
vacuum supply to the SAI control valves is cut off and the valves close to prevent further air
being injected into the exhaust manifold. At the same time as the SAI vacuum solenoid valve is
closed, the ECM opens the ground circuit to the SAI pump relay, to stop the SAI pump.
A vacuum reservoir is included in the vacuum line between the intake manifold and the SAI
vacuum solenoid valve. This prevents changes in vacuum pressure from the intake manifold
being passed on to cause fluctuations of the secondary air injection solenoid valve. The vacuum
reservoir contains a one way valve and ensures a constant vacuum is available for the SAI
vacuum solenoid valve operation. This is particularly important when the vehicle is at high
altitude.
Secondary air injection (SAI) pump
1
SAI pump cover
3
SAI pump
2
Foam filter
4
Pressurized air to exhaust manifolds
The SAI pump is attached to a bracket at the rear RH side of the engine compartment and is
fixed to the bracket by three studs and nuts. The pump is electrically powered from a 12V
battery supply via a dedicated relay and supplies approximately 35kg/hr of air when the vehicle
is at idle in Neutral/Park on a start from 20C (68F).
Air is drawn into the pump through vents in its front cover and is then passed through a foam
filter to remove particulates before air injection. The air is delivered to the exhaust manifold on
each side of the engine through a combination of plastic and metal pipes.
Emission Controls
41
EMISSION CONTROLS
The air delivery pipe is a flexible plastic type, and is connected to the air pump outlet via a
plastic quick-fit connector.
The other end of the flexible plastic pipe connects to the fixed metal pipe work via a short rubber
hose. The part of the flexible plastic pipe which is most vulnerable to engine generated heat is
protected by a heat reflective sleeve. The metal delivery pipe has a fabricated T-piece included
where the pressurized air is split for delivery to each exhaust manifold via the SAI control
valves.
The pipes from the T-piece to each of the SAI control valves are approximately the same length,
so that the pressure and mass of the air delivered to each bank will be equal. The ends of the
pipes are connected to the inlet port of each SAI control valve through short rubber hose
connections.
The T-piece is mounted at the rear of the engine (by the ignition coils) and features a welded
mounting bracket which is fixed to the engine by two studs and nuts.
The foam filter in the air intake of the SAI pump provides noise reduction and protects the pump
from damage due to particulate contamination. In addition, the pump is mounted on rubber
mountings to help prevent noise which is generated by pump operation from being transmitted
through the vehicle body into the passenger compartment.
The SAI pump has an integral thermal cut-out switch, to stop pump operation when the pump
overheats. The pump automatically enters a ’soak period’ between operations, to allow the
pump motor a cooling off period.
If the secondary air injection pump malfunctions, the following fault codes may be stored in the
ECM diagnostic memory, which can be retrieved using ’Testbook’:
P-code
Description
P0418
Secondary air injection pump power stage fault (e.g. - SAI pump relay fault
/ SAI pump or relay not connected / open circuit / harness damage).
Secondary air injection (SAI) pump relay
The secondary air injection pump relay is located in the engine compartment fuse box. The
engine control module (ECM) is used to control the operation of the SAI pump via the SAI pump
relay. Power to the coil of the relay is supplied from the vehicle battery via the main relay and
the ground connection to the coil is via the ECM.
Power to the SAI pump relay contacts is via fusible link FL2 which is located in the engine
compartment fuse box.
42
EMISSION CONTROLS
Secondary air injection (SAI) vacuum solenoid valve
1
Vacuum port to intake manifold
(via vacuum reservoir)
4
Vacuum port to vacuum operated SAI control valves
2
SAI vacuum solenoid valve
5
Purge valve clip
3
Electrical connector
The SAI vacuum solenoid valve is located at the rear LH side of the engine and is electrically
operated under the control of the ECM. The SAI vacuum solenoid valve is mounted on a
bracket together with the EVAP system purge valve.
Vacuum to the SAI vacuum solenoid valve is provided from the intake manifold depression via a
vacuum reservoir. A small bore vacuum hose with rubber elbow connections at each end
provides the vacuum route between the vacuum reservoir and SAI vacuum solenoid valve. A
further small bore vacuum hose with a larger size elbow connector is used to connect the SAI
vacuum solenoid valve to the SAI control valves on each side of the engine via an intermediate
connection. The SAI vacuum solenoid valve port to the SAI control valves is located at a right
angle to the port to the vacuum reservoir.
The intermediate connection in the vacuum supply line is used to split the vacuum equally
between the two SAI control valves. The vacuum hose intermediate connection is located
midpoint in front of the inlet manifold. All vacuum hose lines are protected by flexible plastic
sleeves.
Electrical connection to the SAI vacuum solenoid valve is via a 2–pin connector. A 12V
electrical power supply to the SAI vacuum solenoid valve is provided via the Main relay and
Fuse 2 in the engine compartment fuse box. The ground connection is via the ECM which
controls the SAI vacuum solenoid valve operation.
NOTE: The harness connector to the SAI solenoid valve is grey, and must not be confused with
the harness connector to the EVAP system purge valve which is black.
Emission Controls
43
EMISSION CONTROLS
The ECM switches on the SAI vacuum solenoid valve at the same time as initiating SAI pump
operation. When the SAI vacuum solenoid valve is open, a steady vacuum supply is allowed
through to open the two vacuum operated SAI control valves. When the ECM breaks the earth
path to the SAI vacuum solenoid valve, the valve closes and immediately shuts off the vacuum
supply to the two SAI control valves at the same time as the SAI pump operation is terminated.
If the SAI vacuum solenoid valve malfunctions, the following fault codes may be stored in the
ECM diagnostic memory, which can be retrieved using ’Testbook’:
P-code
Description
P0413
SAI vacuum solenoid valve not connected, open circuit
P0414
SAI vacuum solenoid valve short circuit to ground
P0412
SAI vacuum solenoid valve power stage fault - harness
damage, short circuit to battery supply voltage
SAI control valves
1
Pressurized air from SAI pump
4
Pressurized air to exhaust manifold
2
Vacuum operated SAI control
valve
5
Protective heat sleeve
3
Vacuum hose from SAI vacuum
solenoid valve
6
Air delivery pipe to exhaust manifold
The SAI control valves are located on brackets at each side of the engine.
The air injection supply pipes connect to a large bore port on the side of each SAI control valve
via a short rubber connection hose. A small bore vacuum port is located on each SAI control
valve at the opposite side to the air injection supply port. The vacuum supply to each vacuum
operated SAI control valve is through small bore nylon hoses from the SAI vacuum solenoid
valve. An intermediate connector is included in the vacuum supply line to split the vacuum
applied to each vacuum operated valve, so that both valves open and close simultaneously.
44
EMISSION CONTROLS
When a vacuum is applied to the SAI control valves, the valve opens to allow the pressurized
air from the SAI pump through to the exhaust manifolds. The injection air is output from each
SAI control valve through a port in the bottom of each unit. A metal pipe connects between the
output port of each SAI control valve and each exhaust manifold via an intermediate T-piece.
The T-piece splits the pressurized air delivered to ports at the outer side of the two center
exhaust ports on each cylinder head. The pipes between the T-piece and the exhaust manifold
are enclosed in thermal sleeves to protect the surrounding components from the very high heat
of the exhaust gas, particularly at high engine speeds and loads.
When the SAI vacuum solenoid valve is de-energized, the vacuum supply line opens to
atmosphere, this causes the vacuum operated valves to close automatically and completely to
prevent further air injection.
If the vacuum operated SAI control valves malfunction, the following fault codes may be stored
in the ECM diagnostic memory, which can be retrieved using ’Testbook’:
P-code
Description
P1412
SAI system fault (LH side) - air delivery not reaching catalysts
P1414
SAI system fault (LH side) - air delivery not reaching catalysts
P1413
SAI system fault (LH side) - air delivery not reaching catalysts
P1415
SAI system fault (RH side) - air delivery not reaching catalysts
P1417
SAI system fault (RH side) - air delivery not reaching catalysts
P1416
SAI system fault (RH side) - air delivery not reaching catalysts
The above system faults could be attributable to anything which might prevent air delivery to the
exhaust manifolds (e.g. disconnected or blocked SAI delivery pipe, disconnected or blocked
vacuum pipe etc.)
Emission Controls
45
EMISSION CONTROLS
Vacuum reservoir
1
Vacuum port to SAI vacuum solenoid valve
2
Vacuum port to intake manifold
(one-way valve end)
3
Vacuum reservoir
A vacuum reservoir is included in the vacuum supply line between the intake manifold and the
SAI vacuum solenoid valve. The vacuum reservoir contains a one-way valve, to stop vacuum
from leaking back towards the intake manifold side. The reservoir holds a constant vacuum so
that the SAI control valves open instantaneously as soon as the SAI solenoid valve is
energized.
The vacuum reservoir is a plastic canister construction located on a bracket at the LH side of
the engine compartment.
It is important to ensure the reservoir is installed in the correct orientation, and the correct
vacuum hoses are attached to their corresponding ports. The one-way valve end of the vacuum
reservoir (cap end, to inlet manifold) is installed towards the rear of the vehicle.
A small bore nylon hose is used to connect the one-way valve end of the vacuum reservoir to a
port on the RH side of the inlet manifold. A further hose connects between the other port on the
vacuum reservoir and a port on the front of the SAI vacuum solenoid valve.
46
EVAPORATIVE EMISSION CONTROL SYSTEM
EVAPORATIVE EMISSION CONTROL SYSTEM (EVAP)
EVAPORATIVE PURGE
As gasoline from the fuel tank is pumped to the engine, air must enter the system to prevent a
vacuum from developing. However, harmful hydrocarbon vapors form in the fuel tank as
gasoline evaporates. Venting the fuel tank directly to the atmosphere would allow these vapors
to escape.
To prevent this from occurring, fuel system vapors are routed to a charcoal canister which
absorbs and stores fuel vapor from the tank when the engine is not running. Once the engine is
started, the vapor is purged from the canister by fresh air drawn through an orifice at the base of
the canister and the vacuum introduced at the top.
Evaporative Purge System Components
On 1989 and later vehicles, purge operation is controlled by the ECM through a solenoid valve.
When the valve is opened, the vapor is drawn into the plenum to be added to the air/fuel
mixture. Control of evaporative purge operation is an important ECM function for effective
emission control.
Evaporative emission control system (EVAP)
47
EVAPORATIVE EMISSION CONTROL SYSTEM
When operating, purge flow into the plenum is not accounted for in the ECM's air/fuel
calculations. Because of this, purge operation is saved for those times when the additional
vapor is least likely to affect emissions. Typically, this is when the engine is warm and operating
well above idle speed.
The ECM controls the flow rate by opening, closing, or pulsing the solenoid valve. The ECM
monitors purge flow by looking for signs from the oxygen sensors that the fuel mixture has been
enriched when the solenoid valve is opened. When this no longer occurs, the ECM interprets
this to mean that no more vapor is present. Purge operation is discontinued at this time.
48
EVAPORATIVE EMISSION CONTROL SYSTEM
It is important that purge occur only as long as vapor is present. This reduces the time period in
which unmetered air is introduced into the plenum. A purge solenoid stuck in the open position
will increase vehicle emissions and affect driveability, especially at idle.
Purge Operation
EVAP With Leak Detection
OBDII Legislation requires that the ECM must indicate the occurrence of a fault to the driver, if a
leak in the fuel system allows hydrocarbons to escape to atmosphere. It will do this whenever it
detects leakage greater than a predetermined rate. This rate was initially based upon the
amount permitted to escape through a 1 mm (0. 04”) diameter hole, and for later models, a
0.5mm (0.02”) diameter hole.
Evaporative emission control system (EVAP)
49
EVAPORATIVE EMISSION CONTROL SYSTEM
1
Purge valve
8
Anti-trickle valve
2
Service port
9
Liquid vapor separator
3
Canister Vent Solenoid (CVS)
unit
10
Fuel filler cap
4
Filler neck
11
Roll over valves (ROV's)
5
Charcoal canister breather tube
12
Fuel tank assembly
6
Vent pipe to charcoal canister
13
Charcoal canister
7
Pipe connection to OBD sensor
in fuel pump
14
Purge line connection to engine
manifold
The ECM uses the purge system and a fuel tank pressure sensor to check the integrity of the
fuel system. The ECM purges the charcoal canister of vapor and then closes the charcoal
canister vent valve. This action produces a vacuum within the fuel tank. At a predetermined
vacuum, the purge valve is closed. This action seals the fuel system. The ECM then monitors
the rate at which the pressure within the fuel tank climbs to atmospheric pressure. The rate at
which the pressure equalises is assessed against a ‘model’ (i.e. a pre-programmed map) of fuel
evaporation. If a leak exists, then the pressure will equalize rapidly.
50
EVAPORATIVE EMISSION CONTROL SYSTEM
The ECM completes the purge test only while the vehicle is stationary and the engine is at idle.
The test compensates for the natural evaporation of gasoline, which occurs when it is exposed
to a slight vacuum. If any condition is detected that would produce an excessive level of natural
evaporation levels (e.g. excessive air temperatures or a large degree of movement of fuel within
the fuel tank), the diagnostic is cancelled.
Canister Vent Solenoid Assy.
Purge Control Valve
If the ECM detects a leak in the fuel system (i.e. it has an air leak greater than 1 mm (0. 04”) in
it), it will record a fault code. A loose fuel filler cap can cause the ECM to incorrectly diagnose
an excessive air leak, so always ensure that the fuel filler cap is tight if the ECM has logged a
present fault with the EVAP system. If the ECM records a fault code, the engine speed, engine
coolant temperature and battery voltage is also recorded when the fault is first recognized. If the
ECM detects a fault within the EVAP system on two consecutive ‘journeys’, then it will illuminate
the MIL lamp.
Evaporative emission control system (EVAP)
51
EVAPORATIVE EMISSION CONTROL SYSTEM
Fuel Tank Pressure Sensor
52
ON-BOARD DIAGNOSTICS
ON-BOARD DIAGNOSTICS
The development and adoption of legislation calling for more stringent automotive emission
requirements, initiated by the California Air Resources Board (CARB), is now part of the Federal
Clean Air Act. This legislation is an extension and enhancement of previous requirements
(OBD) and is known as On-Board Diagnostics II (OBD II). Federal law requires that by the 1996
model year, vehicles sold in the United States meet common standards for emission control and
diagnostic capability. GEMS allows Land Rover products to meet these operating standards.
Monitoring Emissions Performance
The original OBD required that vehicles monitor operation of key components such as oxygen
sensors, fuel delivery system, and the module controlling the system's powertrain. Failure of
components in these systems is indicated by MIL illumination and generation of a Diagnostic
Trouble Code (DTC).
OBD II takes this monitoring a step further by not only checking the operation of emission
components, but their performance. While the difference between monitoring operation and
performance may sound small, the changes to ECM operating strategies required to
accomplish this are enormous.
OBD II regulations require the vehicle's MIL to be illuminated and a DTC generated when
system operating conditions are such that vehicle emissions will exceed 15% of the original
emissions specification. DTCs are retrieved using the TestBook or any diagnostic scan tool. All
vehicles meeting OBD II standards use a standardized 16-pin connector for engine
management system diagnostics. The Diagnostic connector on the Range Rover is located in
the front passenger's footwell, near the center console.
16-Pin Connector
On-Board diagnostics
53
ON-BOARD DIAGNOSTICS
Diagnostic Trouble Codes (DTC)
OBD II requires that diagnostic trouble codes for common components are provided by all
manufacturers. These codes must follow the format developed in the Society of Automotive
Engineer's (SAE) standard J2012. This five-digit code consists of four numbers preceded by a
single letter.
Five-Digit DTC
The initial letter designates the vehicle system to which the code refers. All powertrain codes
begin with the letter P. The first number indicates who was responsible for the DTC definition.
The number “0” indicates an SAE defined code required under OBD II while “1” indicates that
this code definition is manufacturer-specific (in this case, Land Rover). The “1” codes allow
manufacturers to develop diagnostic capabilities over and above those required by OBD II.
The third digit (second number) of the powertrain DTC ranges from 0 through 8 and indicates
the specific system subgroup. The fourth and fifth places indicate the specific concern the DTC
addresses.
The number of diagnostic codes that can be produced by the ECM has increased substantially
with the introduction of OBD II. A complete list of P-codes is included at the end of this chapter.
The good news is that these codes are far more specific than those previously available. This
helps technician's pinpoint the cause of a customer concern more quickly than in the past. All
DTCs can be retrieved with a hand held scan tool or T4/WDS.
TestBook
54
ON-BOARD DIAGNOSTICS
Diagnostic System Manager
OBD II requires that more components be monitored for a wider range of “failures” that
previously may have gone unnoticed. Because of this, you can expect the MIL to illuminate
more often than in the past.
Malfunction Indicator Lamp (MIL)
The ECM does, however, contain a special diagnostic strategy or Diagnostic System Manager
(DSM) to help prevent unnecessary MIL illumination. The DSM delays vehicle self-tests, known
as OBD II monitors, until the appropriate operating conditions for the test (engine temperature,
rpm, engine load conditions) are present. This provides the best indicator of fuel system and
emissions control operation under real driving conditions.
The designers of OBD II also recognize that unique operating conditions can produce
emissions that, for a brief period, exceed allowable levels even though engine systems are
operating properly. To prevent these infrequent glitches from triggering the MIL, in most cases
the DSM requires that the system exceed allowable levels on two consecutive test sequences
(known as trips) before the MIL is illuminated.
The DSM software also runs the tests in a specific order. This minimizes the production of
misleading DTCs. If a component or system should fail, there is no sense in performing
additional tests on systems or components which rely on the failed component. They'll fail too!
The GEMS diagnostic strategy doesn't bother to run tests dependent on failed components/
systems until they are operating properly.
OBDII Monitoring
The OBD II system test strategy performs self-diagnostics on related systems (known as
Monitors) as required by federal regulations. These OBD II Monitors are listed below. They will
be covered in greater detail later in the lesson.
•
•
•
•
Misfire Monitor
Comprehensive Component Monitor
Fuel System Monitor
Catalyst Efficiency Monitor
On-Board diagnostics
55
ON-BOARD DIAGNOSTICS
Warm-up Cycle
A term used in discussing OBD II diagnostic strategy is warm-up cycle. The ECM uses the
number of warm-up cycles as a counting device. After a specified number of warm-up cycles
(typically 40) DTCs that are no longer relevant to the engine operating condition are
automatically erased from the ECM’s memory.
This is important from a technician's standpoint because DTCs and information from a concern
that illuminated a customer's MIL at one time may no longer be in the ECM's memory. If the
source of the concern is no longer present (bad gasoline) and the customer has waited a long
time before coming in - you won't find information to work with. On the other hand, old and
irrelevant information isn't likely to be present to mislead you when searching for current
concerns.
The definition of a warm-up cycle is very specific. It includes engine operation, after an engine
OFF period, where engine coolant temperature rises at least 22° C (40° F) and reaches at least
71° C (160° F). It then must cool down below 71° C (160° F).
OBD II Trip
Another important concept is that of the OBD II Trip. This is defined as engine operation after
an engine OFF period, where OBD II components are tested and the following monitors are
completed:
• Misfire
• Comprehensive Component
• Fuel System
The completion of an OBD II Trip is required for most of the new diagnostic strategies that can
produce MIL illumination.
56
ON-BOARD DIAGNOSTICS
OBDII Monitors
The ECM performs a battery of tests on specific vehicle systems to determine if they are
operating within the parameters set by OBD II. The Diagnostic System Manager software
ensures that the tests are performed at specific times and in the correct sequence in order to
produce valid results. Testing the vehicle while cold, or in unusual operating conditions (such
as during evaporative purge) could produce false readings that would illuminate the vehicle's
MIL unnecessarily .
Comprehensive Component Monitor
ECM inputs and outputs are checked frequently during engine operation. As in the original
OBD application, these components and their circuits are checked for operation. Tests for
shorts and opens are performed. Some tests require system or component actuation so a
change of state can be observed. DTCs and MIL illumination occur when a fault is recorded.
OBD II requires even more careful review of these input and output components by not only
determining if they are operating, but also by performing rationality checks. By comparing the
readings from other sensors, the GEMS can determine if a sensor reading is appropriate for the
current operating conditions. An example of this is a throttle position sensor signal indicating
the throttle is half open when other inputs and outputs (rpm, IACV) suggest the engine is at idle.
A specific DTC is stored as soon as a fault is detected. The system must fail the test on two
consecutive drive cycles before the MIL is illuminated.
The GEMS will continue testing failed or out of range components, even after the MIL is
illuminated. Should the system pass the test on three consecutive trips, the MIL will turn off.
The DTC will remain stored however, for 40 more warm-up cycles.
Fuel System Monitor
The ECM continually adjusts fuel trim when in closed loop operation. If a system malfunction
occurs, requiring an amount of fuel trim compensation that exceeds standards set in the GEMS
program, a DTC will be stored. The ECM monitors the fuel system continuously once it is
operating in closed loop.
Should fuel trim requirements fall outside of the acceptable parameters on a second
consecutive trip, the MIL will be illuminated. If the system concern does not repeat itself for
three consecutive trips, the MIL will turn off. The DTC will remain stored for 40 more warm-up
cycles.
NOTE: It is important to understand that two consecutive trips is not the same as two warm-up
cycles. Two consecutive trips could occur two weeks apart, with dozens of warm-up cycles in
between.
On-Board diagnostics
57
ON-BOARD DIAGNOSTICS
Catalyst Efficiency Monitor
The Three-Way Catalyst (TWC) or catalytic converter, is a central device in the vehicle's
emissions control system. Over time, deterioration of a catalyst's operating efficiency can lead
to an increase in hydrocarbon emissions. OBD II requires that the ECM monitor operation of
the vehicle's TWCs to ensure that they are operating within specification. This is accomplished
by monitoring signals produced by oxygen sensors mounted ahead of (upstream) and below
(downstream) of each TWC.
Catalyst Signal
A properly functioning three-way catalyst stores oxygen during lean engine operation and gives
up that stored oxygen during rich engine operation to consume unburned hydrocarbons.
Catalyst efficiency is estimated by monitoring the oxygen storage capacity of the catalyst during
closed-loop operation.
58
ON-BOARD DIAGNOSTICS
The GEMS monitors the switching frequency of the downstream HO2S during the test.
Because the sensor switches in the presence of oxygen, it should have a significantly lower
switching frequency than the sensor mounted ahead of the catalyst.
Rear Catalyst Monitor
A frequency approaching that of the upstream sensor would indicate that the TWC is not storing
oxygen during lean operation. This lack of stored oxygen renders the TWC incapable of
burning off excess hydrocarbons produced during the rich cycle. The result is excessive
hydrocarbon emissions.
Catalyst efficiency is tested once each drive cycle. The first time the system fails a self-test, the
ECM will store a DTC. The system must fail the test on two consecutive drive cycles before the
MIL is illuminated.
The Diagnostic System Manager will continue testing for catalyst efficiency once each drive
cycle, even after the MIL is illuminated. Should the system pass the test on three consecutive
drive trips, the MIL will turn off. The DTC will remain stored, however, for 40 more warm-up
cycles.
Misfire Monitor
Cylinder misfire poses a serious threat to the vehicle's emissions system. Misfires produce
concerns ranging from open ignition circuits to fouled spark plugs. As a cylinder misfires, the
raw hydrocarbons (HC) that should have been consumed during ignition are forced out of the
exhaust manifold. Obviously, this adversely affects vehicle emissions. Worse however, is what
happens after these raw HCs leave the engine and enter the three-way catalyst (TWC).
As these raw hydrocarbons move into the catalyst, the internal temperature of the converter
increases. Continued operation can cause the catalytic honeycomb to melt into a solid mass,
destroying the catalyst's ability to function. Eventually, the TWC may cause so much restriction
that the excessive backpressure prevents the engine from running. Obviously, detecting and
preventing engine operation under misfire conditions is a high priority of an emissions control
system.
On-Board diagnostics
59
ON-BOARD DIAGNOSTICS
The ECM detects engine misfire by measuring the contribution each cylinder makes to engine
performance. This is calculated from measurements of crankshaft acceleration for each
cylinder provided by the crankshaft position sensor.
The acceleration for each cylinder is determined from the crankshaft rotation velocity. The
GEMS performs a series of calculations to determine the acceleration rates of the individual
cylinders. When a cylinder's acceleration falls outside of a predetermined range, the GEMS
takes a closer look at the signal.
For example, operating conditions such as rough roads or high rpm/light load operation can
provide misfire-like changes in crankshaft acceleration. Internal programming in the GEMS is
designed to filter out these look-alike signals and focus on real misfire. The GEMS separates
misfire into two classifications, and has a different response for each.
Type A Misfire:
This is a serious misfire situation where raw fuel entering the TWC can cause excessive catalyst temperatures. This could quickly cause permanent damage to the TWC. In this situation,
the MIL lamp illuminates immediately and flashes to attract the driver's attention. Continued
operation at this point will damage the TWC.
Type B Misfire:
A second type of response occurs when the GEMS detects a low-level misfire. At lower levels,
misfire will not significantly raise TWC temperature but will produce excessive vehicle emissions. In this situation, the GEMS records a DTC. The GEMS will illuminate the MIL if this failure is repeated during a second consecutive drive cycle where operating conditions (engine
warm-up, rpm and load) are approximately the same. Should the misfire not reappear under
these conditions on three consecutive trips, the MIL will turn off.
Crankshaft Acceleration Signal
60
ON-BOARD DIAGNOSTICS
Freeze Frame
OBD II provides a special diagnostic screen known as freeze frame, to help technicians
determine the exact conditions that caused a MIL to be illuminated. Freeze frame traps the
following data the moment a monitor fails:
•
•
•
•
•
•
•
•
•
•
•
•
DTC
Fuel System Status (Open/Closed Loop)
Engine Load*
Coolant Temperature
Short Term Fuel Trim (Bank 1)**
Long Term Fuel Trim (Bank 1)**
Short Term Fuel Trim (Bank 2)***
Long Term Fuel Trim (Bank 2)***
RPM
Vehicle Speed
Intake Air Temperature
Throttle Position
Accessing this data can help you determine the nature of the concern and the steps required to
solve the problem.
* Engine load is represented by a "Calculated load value" which refers to an indication of the
current airflow divided by peak airflow, where peak airflow is corrected for altitude, if available.
This definition provides a unitless number that is not engine specific, and provides the service
technician with an indication of the percent engine capacity that is being used (with wide open
throttle as 100%).
CLV =
Current Airflow
X Atm Pressure (@ sea level)
•Peak airflow (@ sea level)
•Barometric pressure
** Also known as Bank “A”, Odd bank, or left bank
*** Also known as Bank “B”, Even bank, or right bank
On-Board diagnostics
61
ON-BOARD DIAGNOSTICS
Service Drive Cycles
While each of the OBD II monitors is often completed during the course of normal driving, there
is a way to be sure they run in a single driving session. This is called the Service Drive Cycle,
and is of value to technicians diagnosing OBD II concerns.
Plan a test route that will allow you to accomplish the tasks listed. Obey posted speeds and all
traffic laws.
1 Allow vehicle to cold soak until coolant temperature is less than 60° C (140° F).
2 Start engine.
3 Idle for approximately 8 minutes. Diagnostics for misfire, sensors and actuators will run
and produce an outcome. An additional test requiring the engine to run for a total of 15
minutes is present. Idling is the most efficient way to achieve this.
4 Shift to Drive. Accelerate up an incline at wide open throttle to maintain a high engine load
for approximately 10 seconds. This allows Neutral/Drive switch and Road Speed diagnostics to take place.
5 Drive on and off the throttle so that a total of 40 gear changes take place. (Shifts from Park
to Drive or Drive to Neutral don't count toward this total).
6 Accelerate to 35-45 mph and maintain this speed at a steady load for approximately three
minutes. This allows fuel trim adaptations and catalyst monitoring to take place.
7 Slow to idle and place the transmission in Park.
8 Bring the engine to 1500-2000 rpm for approximately one minute.
9 Idle for two minutes, then turn ignition to OFF.
62
LAND ROVER FUEL INJECTION SYSTEMS
LAND ROVER FUEL INJECTION SYSTEMS
INTRODUCTION
Land Rover vehicles use one of two types of electronically controlled fuel injection systems:
Multiport Fuel Injection (MFI) or Sequential Multiport Fuel Injection (SFI).
MULTIPORT FUEL INJECTION (MFI)
Multiport Fuel Injection (MFI) is found on Land Rover models using the Lucas 13 CU, 14 CU,
and 14 CUX engine management systems.
Applications:
• 13CU
1987-1988 Range Rover Classic
• 14CU
1989 Range Rover Classic
• 14CUX
1990-1995 Range Rover Classic
1994-1995 Discovery
1993 Defender 110
1994-1995 Defender 90
SEQUENTIAL MULTIPORT FUEL INJECTION (SFI)
Sequential Multiport Injection (SFI) is used on vehicles equipped with the Sagem/Lucas Generic
Engine Management System (GEMS), and the Bosch Motronic M5.2.1 engine management
system.
Applications:
• GEMS
1995-early 1999 Range Rover
1996-early 1999 Discovery
1997 Defender 90
• Bosch Motronic 5.2.1
1999Range Rover
1999Discovery Series II
Introduction
63
LAND ROVER FUEL INJECTION SYSTEMS
LAND ROVER FUEL SYSTEM COMPONENTS
The following section will provide an overview and comparison of Land Rover fuel system
components in use since 1987. These components will be discussed in the order of Engine
Control Module, System Outputs, and System Inputs.
Engine Control Module (ECM)
13CU
•
•
•
•
•
•
Used 1987 & 1988
Limited on-board self-diagnostics
Adaptive short term fuelling offsets for each bank
Volatile fault memory
Diagnostics with Land Rover/Lucas Hand-Held Tester or TestBook
Mounted under the passenger seat
14CU/14CUX
•
•
•
•
•
•
•
14CU used 1989, 14CUX used 1990-1995
14CU supports adaptive TPS and ISC
EVAP purge control
14CUX has extended memory & supports on-board diagnostics compliant with OBD 1
Volatile fault memory
Replaceable PROM chips
Mounted under the passenger seat on 1989-1994 Range Rover Classic and 1995
Defender; Right side kick panel 1995 Range Rover Classic and Discovery; Under right side
dash 1993 Defender 110 and 1994 Defender 90.
• Diagnostics via On-board display or with Land Rover/Lucas Hand-Held Tester or TestBook
64
LAND ROVER FUEL INJECTION SYSTEMS
GEMS
•
•
•
•
•
•
•
•
•
Used (Range Rover) 1995 to early 1999, (Discovery) 1996- early 1999, (Defender) 1997
Both short term and long term fuelling offsets
Ignition timing control integration
Engine immobilization
OBDII compliant on-board diagnostics
Non-Volatile fault memory
Replaceable PROM chips
Diagnostics with SAE J1962/J1979 compatible tester or TestBook
Mounted in engine compartment
Bosch Motronic 5.2.1
•
•
•
•
•
Used 1999 - present
Additional memory, faster processor/data bus refresh speed
OBDII compliant on-board diagnostics and additional advanced diagnostic capability
Both volatile and non-volatile (LEV) fault memory
EEPROM programmable via data link
• Diagnostics with SAE J1962/J1979 compatible tester or TestBook
Land Rover Fuel System Components
65
LAND ROVER FUEL INJECTION SYSTEMS
FUEL SYSTEM OUTPUTS
Fuel Pump
Fuel Return Type Systems -1987 to 1990
1991-1999
•
•
•
•
•
Used 1987- early 1999
Integral fuel level sending unit beginning 1991
In-tank with external fuel filter
2.4-2.6 bar (34-37 psi) operating pressure
Key off pressure drop from 2.3-2.6 bar (36-38 psi)- less
than 0.7 bar (10 psi) in one minute
• Integral Advanced EVAP sensor from October 1996
Non-Return Type System
•
•
•
•
66
Used with Bosch EMS 1999- present
Integral fuel pressure regulator
3.5 bar (50.75 psi) operating pressure
Integral advanced EVAP sensor 1999-present (Except LEV Phase II vehicles)
LAND ROVER FUEL INJECTION SYSTEMS
Fuel Filter
Return Type Systems
• External 1987-1999
• Mounted on the chassis, near the passenger-side rear wheel arch. An arrow on the filter
body indicates the direction of fuel flow.
• Worm clamps 1987-1990
• O-Ring and Fitting 1991- early 1999
Non-Return Type System
•
•
•
•
1999- present (Bosch EMS)
Integral with fuel pump
Coarse gauze filter in swirl pot
Fine paper filter around pump inlet
Fuel Pressure Regulator
Return Type Systems
• Mounted on fuel rail
• No service adjustments
• Adjusts pressure relative to intake manifold pressure
Fuel System Outputs
67
LAND ROVER FUEL INJECTION SYSTEMS
NON-RETURN TYPE SYSTEM
• Mounted on fuel pump
• No service adjustments
• Adjusts pressure relative to atmospheric pressure
Fuel Injectors
13CU, 14CU
• Machined Needle Valve type.
• Approx. 16W resistance per injector
• Flow rate = 180-195cc (using gasoline) minimum at 2.5 bar (36 psi) at 20°C (68°F)
14CUX, GEMS
• Moveable Disc and Rod type.
• 16.2W ±0.5W resistance per injector at 20°C (68°F)
• Flow rate = 180-195cc (using gasoline) minimum at 2.5 bar (36 psi) at 20°C (68°F)
Motronic 5.2.1
• Fixed Disc and Ball-ended pintle type.
• 14.5W ±0.7W resistance per injector at 20°C (68°F)
NOTE: Injector Testing Note:The preferred method for testing all Land Rover fuel injectors is
using the procedure outlined in TIB 19/02/97/NAS. This method checks for nozzle leakage, and
also specifies that the fuel pressure drop the injectors. Each injector should be within ±13.8
68
LAND ROVER FUEL INJECTION SYSTEMS
kpa (2 psi) of all the other injectors when pulsed for 500ms with the test equipment.
Idle Air Control Valve (IACV)
13CU, 14CU, 14CUX
• Bipolar stepper motor controlling a screw-mounted tapered valve
• Active when: Road speed less than 3 mph; Throttle closed; Engine above 50 rpm
• Air valve open = 0 steps
Air valve closed = 180 steps
• Base idle is controlled through a separate bypass port located in the housing for the throttle
butterfly.
GEMS
• Similar in operation as 13/14CU, 14CUX
• Air valve open = 200 steps (180 steps for vehicles up to 97MY)
Air valve closed = 0 steps
• Base idle is controlled through a separate bypass port located in the housing for the throttle
butterfly.
Motronic
• Pulse Width Modulated 2-winding motor, controlling a rotary valve within an idle air flow
passage
• No base idle adjustments
Fuel System Outputs
69
LAND ROVER FUEL INJECTION SYSTEMS
FUEL SYSTEM INPUTS
Heated Oxygen Sensor (HO2S)
13CU, 14CU,14CUX
• One heated sensor for each bank, located upstream of the catalysts
• 3-wire resistive titanium sensor element
Sensor power supplied from heater element
• Constant voltage supply to heater elements
GEMS
• Two heated sensors per bank, one pre-catalyst, one post-catalyst. Post-catalyst sensor
used only to monitor catalyst efficiency.
• 4-wire resistive titanium sensor element
5v supply from ECM
• Pulse Width Modulated voltage supply to heater elements
Motronic
• Two heated sensors per bank, one pre-catalyst, one post-catalyst. Post-catalyst sensor
used only to monitor catalyst efficiency.
• 4-wire voltage generating Zirconium sensor element
• Pulse Width Modulated voltage supply to heater elements
• Front and Rear sensors are different
70
LAND ROVER FUEL INJECTION SYSTEMS
Sensor Operation Notes
Resistive Sensors• Uses a voltage supply through the sensor element
• Resistance increases under lean conditions
Resistance decreases under rich conditions
Voltage Generating Sensors• Generates voltage (up to 1.1 v) under rich conditions - high voltage measured at sensor
Low or No voltage generated under lean conditions - low voltage measured at sensor
Mass Air Flow Sensor (MAFS)
13CU, 14CU, 14CUX
• Hot Wire type
• No additional intake air temperature sensor used
GEMS
• Hot Wire type
• Uses additional intake air temperature sensor
Motronic
• Hot Film type
• Uses additional intake air temperature sensor
Fuel System Inputs
71
LAND ROVER FUEL INJECTION SYSTEMS
Throttle Butterfly
13CU, 14CU, 14CUX, GEMS
• Must be perpendicular within the bore
• Close tolerence between plate and bore- particular attention should be paid to deposit
build-ups
• Coolant-fed pre-heating passage underneath housing/plate area
• Cable slack is adjustable
• Linkage and stop screw wear may allow plate to ‘flip backwards’ slightly in bore
• Adjustment must be made using a depth gauge
• 1987 Models have adjustment screw mounted on throttle lever, all others have screw
mounted in housing as shown
Motronic
• No plate adjustment normally needed
• Cable slack is adjustable
• Coolant-fed pre-heating passage underneath housing/plate area
72
LAND ROVER FUEL INJECTION SYSTEMS
Throttle Position Sensor (TPS)
13CU
• Adjustable- ECM DOES NOT adapt
• Voltage Range 0.29-0.36v throttle closed
4.2-4.8v throttle open
14CU
• Non-Adjustable- ECM is adaptive
• Voltage Range 0.085-0.545v throttle closed
4.2-4.9v throttle open
14CUX
• Non-Adjustable- ECM is adaptive
• Voltage Range 0.083-0.547v throttle closed
4.7-4.9v throttle open
GEMS
• Non-Adjustable- ECM is adaptive
• Voltage Range approx. 0.6v throttle closed
approx. 4.5v throttle open
Fuel System Inputs
73
LAND ROVER FUEL INJECTION SYSTEMS
Motronic
• Non-Adjustable- ECM is adaptive
• Voltage Range 0.29-0.36v throttle closed
4.2-4.9v throttle open
Engine Coolant Temperature Sensor (ECT)
13CU/14CU/14CUX
• NTC type sensor
• Resistance range = approx. 9200W at -10°C (-22°F) to 175W at 100°C (212°F). Approx.
300W at 80°C (176°F).
• ECM fault default value = 36°C (96.8°F).
• Located at the top front of the engine, to the right of the alternator and in front of the plenum
chamber.
GEMS
• NTC type sensor
• Output = Approx. 4.7v at -30°C (-22°F) to 0.25v at 130°C (302°F). Approx. 0.7v at 85°C
(185°F)
• ECM fault default value = dependant on value of air temperature sensor
• Located at the top front of the engine, to the right of the alternator and in front of the plenum
chamber.
Motronic
• NTC type sensor
• Sensor contains two elements, only one is used on Discovery, on Range Rover one is also
used for the instrument temperature gauge.
• Output = Approx. 4.9v at -50°C (-58°F) to 0.75v at 130°C (266°F). Approx. 1.8v at 70°C
(158°F)
• ECM fault default value = dependant on software map up to 60°C (140°F), after which
74
LAND ROVER FUEL INJECTION SYSTEMS
defaults to 85°C (185°F)
• Located at the top front of the engine, to the right of the alternator and in front of the plenum
chamber.
Engine Fuel Temperature Sensor (EFT)
13CU/14CU/14CUX
• NTC type sensor
• Range = 9.1k-W at -10 °C (14°F) to 150W at 100°C (212°F). Approx. 1.2 k-W at 40°C
(104°F)
• Located on the fuel rail forward of the intake housing, between left and right injector banks
GEMS
• NTC type sensor
• Range = 23k-W at -30 °C (-22°F) to 290W at 80°C (176°F). Approx. 1.1 k-W at 40°C
(104°F)
• Located on the fuel rail by cylinders 3 and 5
Motronic
• None used
Intake Air Temperature Sensor (IAT)
13CU/14CU/14CUX
• None used
GEMS
•
•
•
•
NTC type sensor
Retards ignition timing above 55°C (131°F)
Range = 23k-W at -30 °C (-22°F) to 290W at 80°C (176°F)
Located in air cleaner housing
Fuel System Inputs
75
LAND ROVER FUEL INJECTION SYSTEMS
Motronic
•
•
•
•
NTC type sensor
Range = 4.75v at -40 °C (-40°F) to .25v at 130°C (266°F)
Default fault value = 45°C (113°F)
Integral with Mass Air Flow Sensor
Knock Sensor
13CU/14CU/14CUX
• None used
GEMS
• Two used- mounted on the cylinder block between the two center cylinders of each bank
• Voltage output increases with severity of knock detected
Motronic
• Same location and operation as GEMS
76
LAND ROVER FUEL INJECTION SYSTEMS
OPEN AND CLOSED LOOP OPERATION
CLOSED LOOP OPERATION
During closed loop, or feedback operation, the ECM controls fuel system operation based on
information provided by the various vehicle inputs. Because these inputs represent actual
operating conditions, the system is most able to meet performance and efficiency targets when
operating in closed loop.
The primary input during closed loop operation is the oxygen sensor since it indicates the result
of the combustion process, regardless of the engine speed and load.
The primary output during closed loop operation is the fuel injector timing and duration.
All other sensors generally serve to help the ECM ‘trim’ or anticipate the operation of the engine
to meet a particular oxygen sensor value or known tailpipe emission condition.
OPEN LOOP OPERATION
At times (start-up, full throttle) engine operating requirements may fall outside the bounds of
that suggested by the ECM inputs. Some sensors do not operate at peak efficiently until warm.
At these times, the ECM substitutes a pre-programmed set of reference inputs that are most
likely to produce desired engine operation. This is referred to as open loop operation.
The system may also default to open loop operation when component failure provides an input
signal outside the range of known parameters recognized by the ECM. The ECM will substitute
a signal value that allows the vehicle to continue to operate. The Malfunction Indicator Lamp
(CHECK ENGINE) on the instrument panel is illuminated at this time to indicate the failure of an
emissions-related component.
Open and Closed Loop Operation
77
LAND ROVER FUEL INJECTION SYSTEMS
78
13/14CU AND 14CUX SYSTEMS
13/14CU AND 14CUX SYSTEMS
Introduction
Three variations of similar Lucas engine management systems have been used on Land Rover
vehicles from 1987 to selected 1995 models. Operation of each of these systems is
fundamentally the same, the differences between each being enhancements to self diagnostics,
improved adaptability to operating conditions, and additional input/output capability. All of these
systems utilize a Engine Control Module, and all are tied to vehicle inputs and outputs through a
similar 40 pin connector.
The systems used are:
• 13 CU (1987-88)
• 14 CU (1989)
• 14 CUX (1990-95)
The system control modules are mounted under the passenger seat on 1987-1994 vehicles.
The module is moved to a position just behind the glove box on 1995 models.
The ECM works with system inputs and outputs to deliver the best possible combination of
engine performance and economy while minimizing vehicle emissions.
13 CU
The 13 CU module receives the following inputs:
•
•
•
•
•
•
•
•
•
•
•
•
Key on
Battery voltage
Throttle Position Sensor (TPS)
Engine speed
Engine Fuel Temperature (EFT) sensor
Engine Coolant Temperature Sensor (ECT)
Heated Oxygen Sensor (HO2S)
Mass Air Flow Sensor (MAF)
Vehicle Speed Sensor (VSS)
Park/Neutral Position Switch (PNPS)
Air Conditioning Fan and Mode Switch
Heated Rear screen load (1987 only)
13/14CU and 14CUX Systems
79
13/14CU AND 14CUX SYSTEMS
The following are 13 CU outputs:
•
•
•
•
•
Fuel Injectors
Idle Air Control Valve (IACV)
Malfunction Indicator Lamp (MIL)
Fuel Pump/ Oxygen Sensor Heaters Relay
Main relay
13CU System Inputs and Outputs
80
13/14CU AND 14CUX SYSTEMS
14CU and 14CUX
The 14CU and 14CUX modules include additional inputs and output controls for more precise
control of the air-fuel mixture and enhanced self-diagnostic capabilities.
The following are ECM inputs:
•
•
•
•
•
•
•
•
•
•
•
•
•
Key on
Battery voltage
Throttle Position Sensor (TPS)
Engine speed
Engine Fuel Temperature (EFT) sensor
Engine Coolant Temperature Sensor (ECT)
Heated Front Screen
Heated Oxygen Sensor (HO2S)
Mass Air Flow Sensor (MAF)
Vehicle Speed Sensor (VSS)
Park/Neutral Position Switch (PNPS)
Air Conditioning Fan Switch (14CU only)
Air Conditioning Thermostat
The ECM outputs are as follows:
•
•
•
•
•
•
•
•
•
Fuel Injectors
Idle Air Control Valve (IACV)
Purge Valve (CANPV)
A/C Compressor Clutch
A/C Condenser Fan Control Module (FCM)
Malfunction Indicator Lamp (MIL)
Fuel Pump/ Oxygen Sensor Heaters Relay
Main relay
Fault Code Display Unit (14CUX only)
13/14CU and 14CUX Systems
81
13/14CU AND 14CUX SYSTEMS
14CUX Inputs and Outputs
82
13/14CU AND 14CUX SYSTEMS
SYSTEM INPUTS
Mass Air Flow Sensor (MAF)
The Mass Air Flow (MAF) sensor is a hot-wire type. It contains two wires, one heated to a
known value of 100° C (212° F) above the other. As air flow increases, the current required to
maintain this difference in temperature increases. The air flow meter's circuitry converts this
current requirement into a signal the ECM uses to determine the amount of air entering the
intake manifold.
Typical MAF output voltage at idle is between 1.3 and 1.5 VDC. A diagnostic trouble code (12)
is produced if MAF voltage is:
• less than 122 mV with RPM in excess of crank speed.
• greater than 4.96 V with RPM less than 976 for more than 160 milliseconds.
Mass Air Flow Sensor
13/14CU and 14CUX Systems
83
13/14CU AND 14CUX SYSTEMS
Throttle Position Sensor (TPS)
This potentiometer is mechanically linked to the throttle butterfly and provides an output voltage
proportional to the butterfly position. This information allows the ECM to determine throttle
position and is used for ECM strategies like the following:
• Acceleration Enhancement - The ECM increases the amount of fuel normally provided for a
given throttle position during periods of peak acceleration. This allows the system to anticipate fuel needs.
• Deceleration Fuel Shut-off - During throttle closed deceleration, the ECM does not activate
fuel injectors (zero pulse-width) to prevent unneeded fuel from entering the cylinders. This
strategy protects against catalytic converter overheating and reduces fuel consumption.
13 CU throttle position sensors must be set to an initial output reading of 290-360 mV when
installed. Gradual loosening of the TPS or damage to the throttle stop could cause the sensor
to move out of range.
14 CU and CUX throttle circuitry is adaptable within a range of 80 to 500 mV. Within this range,
the PCM will adapt to the initial setting and use it as a reference. There is no need to adjust the
TPS following installation on these models. If the TPS should fail, the ECM will use a default
value of 576 mV and the MIL will be illuminated.
A diagnostic trouble code (17) is set when sensor output is less than 78 mV for longer than 160
milliseconds.
Throttle Position Sensor
84
13/14CU AND 14CUX SYSTEMS
Engine Coolant Temperature Sensor (ECTS)
The ECTS is a resistor based sensor. As coolant temperature increases, sensor resistance
decreases. The ECM uses this information for hot- and cold-start strategies that require
additional fuel delivery. It also uses this information to help determine when to enter closed loop
operation.
A diagnostic trouble code (14) is stored when the signal is out of range (0.15V to 4.9V) for
longer than 160 milliseconds. The MIL will illuminate and the ECM will substitute a default value
of 36° C (97° F).
Coolant Temerature Sensor Response
Engine Fuel Temperature Sensor (EFTS)
The fuel temperature sensor, mounted on the fuel rail, operates in the same manner as the
ECTS. When the ECM receives a high fuel temperature input, it increases injector pulse during
hot restarts. When fuel is hot, vaporization occurs in the fuel rail and bubbles may be found in
the injectors. This can lead to hard starting. Increasing injector pulse time flushes the bubbles
away and cools the fuel rail with fresh fuel from the tank. Since 1989, the EFTS has also been
used by ECM to trigger operation of the radiator fans when under-hood temperatures become
extreme.
As with the engine coolant temperature sensor, a diagnostic trouble code (15 [14CUX only]) is
stored when the signal is out of range (0.08V to 4.9V) for longer than 160 milliseconds. No
default value is provided by the ECM, however the MIL will illuminate.
13/14CU and 14CUX Systems
85
13/14CU AND 14CUX SYSTEMS
Heated Oxygen Sensor (HO2S)
The heated oxygen sensor is mounted in each exhaust downpipe and is used by the ECM to
determine whether the engine is operating rich or lean. The ECM uses this information to
increase or decrease injector pulse width to bring the air/fuel ratio as close to Stoichiometric as
possible. The ECM monitors each sensor separately and makes fuel trim adjustments to each
cylinder bank independent of the other.
Typical Heated Oxygen Sensor
Oxygen sensors operate efficiently only when warm. Heated sensors reach operating
temperatures quickly to provide accurate information to the ECM soon after start-up and allow
closed loop operation to occur sooner. This helps provide an efficient fuel mixture during engine
warm-up and guards against catalytic converter overheating.
The sensors operate in a range of 0 to 1.1 VDC. To avoid the possibility of interference in this
narrow range of operation, each input wire is shielded against RF interference.
Diagnostic trouble codes (44/45) are produced if either HO2S will not switch after the ECM has
radically altered fueling on that bank of injectors. The test is performed when the engine is at
normal operating temperature, TPS input is above 2 volts, and a road speed input is received.
86
13/14CU AND 14CUX SYSTEMS
Park/Neutral Position Switch (PNPS)
The ECM uses this information on transmission gear selection to determine correct positioning
of the Idle Air Control (IACV) valve. A diagnostic trouble code (69 [14CUX only]) is set when
sensor voltage is 5 V during cranking or 0 V with RPM above 2663 and MAFS voltage above 3
V.
Engine Speed
The ECM determines engine speed from data received through the negative coil lead. A
dropper resistor (6800 ohms) reduces the voltage at the ECM to approximately 7 volts. The
ECM requires a pulse from the ignition system before energizing injectors.
Coil Leads
13/14CU and 14CUX Systems
87
13/14CU AND 14CUX SYSTEMS
Vehicle Speed Sensor (VSS)
The Vehicle Speed Sensor is located on the left hand side of the frame on early models, and on
the left hand side of the transfer case on later models. It informs the ECM when vehicle speed
is above or below 3 mph. This information is used by the ECM to ensure that the idle air control
valve (IACV) is moved to a position to prevent a stall when the vehicle comes to a stop. DTC 68
will be displayed if the MAF is greater than 3V at 2000-3000 RPM’s
Vehicle Speed Sensor 1987-1995
Vehicle Speed Sensor 1995- Onward
88
13/14CU AND 14CUX SYSTEMS
A/C Fan Switch Input (13CU and 14CU only)
This indicates that heater or A/C blower motor operation has been requested via the dash
control panel. On 13CU systems, this is the only Air Conditioning system input signal. The
ECM will compensate for the additional engine load and adjust idle speed accordingly. On
14CU systems, this signal is used in combination with the A/C thermostat input signal.
A/C Thermostat Input (14CU and 14CUX only)
By indicating when the A/C compressor is operating, the ECM can compensate for the
additional engine load and adjust idle speed accordingly. On 14CU systems this signal comes
from the A/C thermostat, through the A/C high pressure switch. On 14CUX, this signal comes
from the A/C thermostat control unit.
Heated Rear Screen (1987 M.Y. 13 CU only)
By indicating when the heated rear screen is in use, the ECM can compensate for the additional
load the generator produces on the engine by adjusting the idle speed.
Heated Front Screen (14 CU and 14 CUX only)
By indicating when the heated front screen is in use, the ECM can compensate for the
additional load the generator produces on the engine. The ECM will then adjust the idle speed
accordingly.
PIN
13CU
ECM
5
21
Heated Rear Screen (1987 only)
A/C Blower Fan/Mode Switch
Idle (Stepper) Control
, 26, 28, 29
PIN
14CU
ECM
5
8
21
Heat & A/C Blower Fan Switch
Heated Front Screen
A/C Thermostat/Pressure Switch
33
A/C Compressor Clutch Control
1, 26, 28, 29
Idle (Stepper) Control
PIN
14CUX
ECM
8
21
Heated Front Screen
A/C Thermostat Unit
33
A/C Compressor Clutch Control
1, 26, 28, 29
13/14CU and 14CUX Systems
Idle (Stepper) Control
89
13/14CU AND 14CUX SYSTEMS
OUTPUTS
Main relay
The ECM provides power to both fuel injector banks, MAFS, the fan module, and fault display
via the main relay. The relay is located under the passenger seat on most models. For 1995,
the relay has been moved to the engine compartment where it is mounted on the passenger
side fender wall. On Defender, the relay is mounted on the passenger side of the bulkhead.
Fuel Pump Relay
The fuel pump relay is located next to the main relay. The ECM provides power to the fuel
pump, HO2S heaters and purge valve through the fuel pump relay. The ECM operates the fuel
pump for one second at key on and then when it senses a crank/run signal from the ignition
system.
Relay Locations 1987-1995Relay Locations 1995
90
13/14CU AND 14CUX SYSTEMS
Fuel Injectors
The ECM provides ground side switching to both A (pin 13) and B (pin 11) injector banks.
Banks are operated alternately except at start-up when simultaneous operation is used to
provide additional fuel to the system. Injectors are shut off during deceleration.
The ECM controls fuel volume through injector pulse width. Pulse width varies between
approximately 2.4 milliseconds at idle to a maximum of approximately 9.0 milliseconds at full
load. Each injector has a resistance of 16 ohms. Resistance value of the complete injector
circuit (wired in parallel) will be approximately 4 ohms.
Idle Air Control Valve (IACV)
The idle air control "stepper motor" operates through a range of 180 steps with the 0 position
completely open and the 180 position fully closed. The further open the valve is positioned, the
higher the idle speed will be. Idle position on a vehicle at normal operating temperature with no
engine load is approximately 160. The ECM opens the valve a fixed number of steps in
response to input signals from load producing items such as the air conditioning compressor,
front defroster, and transmission shifting out of Park/Neutral. Resistance in the IACV coils
ranges from 40-60 ohms at room temperature and up to 70 ohms when hot.
Malfunction Indicator Lamp (MIL)
Formerly known as the CHECK ENGINE lamp, the MIL illuminates when the ECM determines
an emissions-related component has failed. The MIL also illuminates at key-on and vehicle
start-up to test bulb operation.
Purge Valve (CAN PV) 14 CU, 14 CUX only
Land Rover vehicles contain an evaporative emission system designed to capture vapors
produced by the vehicle's fuel system. Evaporative emissions from the fuel tank are trapped in
a carbon filled canister before they can reach the atmosphere. These vapors are then vented to
the plenum chamber through a purge valve during engine operation. The ECM pulses the valve
open for short periods below 1700 RPM and holds it open at higher speeds once the engine has
achieved operating temperature and is in closed loop. Operating temperature is defined as
engine coolant temperature above 54° C (130° F).
The ECM monitors the need for canister purge by looking at HO2S response when the valve is
opened. No change in HO2S response with the valve open indicates that the canister has been
purged of fuel vapor and continued valve operation is no longer necessary. Operation of the
purge function when no longer required can negatively impact vehicle emissions.
A/C Compressor Relay
The ECM controls operation of the electronic A/C clutch through this relay. The ECM provides
a ground path for the relay circuit when it receives a request for A/C operation from the A/C
control panel.
Fan Control Module (FCM)
The ECM remains powered for approximately five seconds after the ignition is switched to OFF.
During this time, it monitors under-hood temperature through the engine fuel temperature
sensor. If measured temperatures exceed 70° C (150° F), the ECM grounds the fan control
module, allowing the condenser fans to run for ten minutes.
13/14CU and 14CUX Systems
91
13/14CU AND 14CUX SYSTEMS
Inertia Switch
The inertia switch isolates the power supply to fuel pump in the event of extreme deceleration
like that which would occur in a collision. The inertia switch is located under the left front seat
on 1987-1994 vehicles, and on the bulkhead at the back of the engine compartment from 1995.
It can be reset by pressing the button at the top of the switch.
Inertia Switch 1987-1994
Inertia Switch 1995
92
13/14CU AND 14CUX SYSTEMS
Engine On-Board Diagnostic (OBD) System
Much of the new technology introduced on these engine control systems is directed toward
improving the quality of exhaust gas emissions and reducing air pollution. Much of this has
been mandated by legislation that originated with the California Air Resources Board (CARB).
Control system self-diagnostics, or On-Board Diagnostics (OBD) for vehicle emissions are
included in the 14 CUX engine control system.
OBD regulations produced by CARB require that vehicles monitor operation of key emissions
components such as the oxygen sensor, fuel delivery system, and ECM. Failure of components
in these systems is indicated by the illumination of a CHECK ENGINE or Malfunction Indicator
Lamp (MIL) on the instrument cluster.
On-board Fault Display Unit
Diagnostic Trouble Codes (DTCs) are provided to help direct the technician to the source of the
concern. They can be retrieved with the TestBook or the Lucas HHT.
Codes are also displayed on 1990-1995 models, via the on-board fault display. No additional
diagnostic equipment is required and if a system fault exists, it is displayed any time the ignition
switch is in the ‘on’ position. Any additional faults are displayed in order of system priority, but
only one at a time.
The following procedure displays the codes, and clears the fault memory:
1 Switch On ignition.
2 Disconnect serial link mating plug, wait 5 seconds, reconnect.
3 Switch OFF ignition, wait for main relay to drop out.
4 Switch ON ignition. The display should now reset. If no other faults exist, and the original
fault has been rectified, the display will be blank.
5 If multiple faults exist repeat Steps 1 to 4. As each fault is cleared the code will change,
until all faults are cleared. The display will now be blank.
13/14CU and 14CUX Systems
93
13/14CU AND 14CUX SYSTEMS
System Fault Codes
13CU and 14CU systems have a limited number of self-diagnostic fault codes, however all of
the basic system areas such as Oxygen Sensors, Throttle Potentiometer, Air Flow Sensor, and
Coolant Sensor are monitored.
14CUX sytems are OBD (I) compliant, and will display the following faults, which are listed in
order of display priority:
94
Code
Description
02
ECM Power Disconnected (displays only until first key on/key
off cycle)
29
ECM Memory Check
44
Lambda Sensor A
45
Lambda Sensor B
25
Ignition Misfire
40
Misfire Bank A
50
Misfire Bank B
12
Airflow Meter
21
ECM Tune Select
34
Injector Bank A
36
Injector Bank B
14
Coolant temperature Sensor
17
Throttle Potentiometer
18
Throttle Potentiometer high while Airflow Meter low
19
Throttle Potentiometer low while Airflow Meter high
88
Purge Valve
28
Intake System Air Leak
23
Fuel Supply
48
Stepper Motor
68
Road Speed Sensor
69
Automatic Transmission Gear Switch
59
Fuel Supply or Air Leak Group fault
15
Fuel Temperature Sensor
13/14CU AND 14CUX SYSTEMS
SYSTEM DIAGNOSTICS
A technician's approach to diagnostics of any vehicle system should include the following steps:
•
•
•
•
•
Verify the customer concern
Determine related symptoms
Isolate the source of the concern
Perform the required repair
Verify system operation
As indicated, the first step in vehicle diagnosis is verification of the customer's concern. This
can eliminate time spent unnecessarily searching for the cause of a normal operating condition.
An example of this might be changes in engine idle during times of high accessory load.
The next step in diagnosing the concern is to determine related symptoms and narrow them
down to a specific vehicle system. Retrieving diagnostic trouble codes (DTCs) is recommended
at this stage of diagnosis. Vehicles using the 13 through 14 CUX series controllers allow limited
self-diagnostics, including code retrieval, using the TestBook or Hand Held Tester.
Diagnostic Connector
The 14 CUX communicates with diagnostic test equipment (TestBook) through connector pins
18 and 9. These pins can be accessed through a harness located under the passenger seat on
most models. For the 1995 model year, the harness is located behind the glove box. Search
for the harness carefully as it may be tucked in among other wiring.
13/14CU and 14CUX Systems
95
13/14CU AND 14CUX SYSTEMS
Using this diagnostic connector allows you to perform system diagnostics without removing the
harness connector from the ECM and clear codes without diagnostic equipment.
Diagnostic Connector Locations
96
13/14CU AND 14CUX SYSTEMS
TestBook Connections
Selecting the correct accessory cables is critical when using the TestBook for system diagnosis.
Cables can vary for each application.
Once you have selected the proper cables, ensure that they are securely connected and
plugged into Socket 1 at the back of the TestBook unit. Next, connect the clip on the power lead
to the positive (B+) post of the vehicle's battery. You are now ready to enter TestBook
diagnostics.
TestBook Diagnostic Connector Hook-up
Once past the main menu, TestBook offers a selection of vehicle systems that can be tested.
These include:
•
•
•
•
EFI
Air Suspension
ABS
Airbag
The air suspension selection is available only on Range Rover Classic.
13/14CU and 14CUX Systems
97
13/14CU AND 14CUX SYSTEMS
Touch the system icon to move on to the next selection screen.
TestBook provides you with the opportunity to monitor the function of the system inputs listed on
the screen below.
98
13/14CU AND 14CUX SYSTEMS
The screen below provides you with an example of the information available under the icon
LAMBDA BANK B. (Lambda is another term for oxygen sensor.) This is an example of how
TestBook allows you to monitor sensor operation as the engine is operating.
Information is provided on the screen to help you determine if the component is operating within
specified parameters. This screen is also helpful in verifying operation following a repair.
13/14CU and 14CUX Systems
99
13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX ECM Connector Pin-Outs
1987-88 Lucas 13 CU ECM
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE COLOR
FUNCTION
1
RG
Stepper “D”
21
YU
A/C clutch input
2
NO
Battery + Main Relay
22
UR
AFM Idle trim
3
Y
TPS Reference voltage
23
U
Lambda Bank “A”
4
B
Lambda ground
24
U
Lambda Bank “B”
5
NP
(1987) Rear Screen input
(1988) N.C.
25
RB
Sensor “VE”
6
Y
Vehicle Speed input
26
GW
Stepper “C”
7
GU
Water Temperature input
27
BS
Signal Ground
8
-
28
US
Stepper “B”
9
WLG
Serial Link
29
O
Stepper “A”
10
BY
“EFI” Light (MIL)
30
-
11
YW
Bank “B” injector ground
31
-
12
UR
Main Relay Request
32
SW
13
YU
Bank “A” injector ground
33
-
14
B
ECM Ground
34
OB
Park/Neutral input
15
N
Battery +
35
UG
AFM input
16
UP
Fuel Pump Relay Request
36
-
17
-
37
WY
18
WK
Serial Link
38
-
19
WS
Ignition “ON” input
39
WB
Tachometer input
20
R
TPS input
40
B
ECM ground
100
Fuel Temperature input
Serial Link
13/14CU AND 14CUX SYSTEMS
1989 Lucas 14 CU ECM
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE COLOR
FUNCTION
1
RG
Stepper “D”
21
YB
A/C clutch input
2
NO
Battery + Main Relay
22
UR
AFM Idle trim
3
Y
TPS Reference voltage
23
U
Lambda Bank “A”
4
B
Lambda ground
24
U
Lambda Bank “B”
5
BW
A/C Fan Switch Input
25
RB
Sensor Signal Ground
6
Y
Vehicle Speed input
26
GW
Stepper “C”
7
GU
Water Temperature input
27
BS
Ground
8
PY
Heated Front Screen input
28
US
Stepper “B”
9
WLG
Serial Link
29
O
Stepper “A”
10
BY
“EFI” Light (MIL)
30
-
11
YW
Bank “B” injector ground
31
-
12
UR
Main Relay Request
32
SW
Fuel Temperature input
13
YU
Bank “A” injector ground
33
BS
A/C clutch output
14
B
ECM Ground
34
OB
Park/Neutral input
15
N
Battery +
35
UG
AFM input
16
UP
Fuel Pump Relay Request
36
BG
Fan Timer Request
17
SY
Purge Control
37
WY
Serial Link
18
WK
Serial Link
38
-
19
WS
Ignition “ON” input
39
WB
Tachometer input
20
R
TPS input
40
B
ECM ground
13/14CU and 14CUX Systems
101
13/14CU AND 14CUX SYSTEMS
1990-95 Lucas 14 CUX ECM
C243
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE COLOR
FUNCTION
1
RG
Stepper “D”
21
YB
A/C clutch input
2
NO
Battery + Main Relay
22
UR
AFM Idle trim
3
Y
TPS Reference voltage
23
U
Lambda Bank “A”
4
B
Lambda ground
24
U
Lambda Bank “B”
5
BW
Tune Resistor (1990 only)
25
RB
Sensor “VE”
6
Y
Vehicle Speed input
26
GW
Stepper “C”
7
GU
Water Temperature input
27
BS
Signal Ground
8
PY
Heated Front Screen input
28
US
Stepper “B”
9
WLG
Serial Link
29
O
Stepper “A”
10
BY
“Check Engine” Light (MIL)
30
K
Fault Display output
11
YW
Bank “B” injector ground
31
BG
Diagnostic Reset
12
UR
Main Relay Request
32
SW
Fuel Temperature input
13
YU
Bank “A” injector ground
33
BS
A/C Clutch output
14
B
ECM Ground
34
OB
Park/Neutral input
15
N
Battery +
35
UG
AFM input
16
UP
Fuel Pump Relay Request
36
BG
Fan Timer Request
17
SY
Purge control
37
-
18
WK
Serial Link
38
NK
Fault Clock output
19
WS
Ignition “ON” input
39
WB
Tachometer input
20
R
TPS input
40
B
ECM ground
Heated Oxygen Sensor X139, X160
102
13/14CU AND 14CUX SYSTEMS
1
2
3
3way-Black
PIN
WIRE
COLOR
FUNCTION
1.00
WO
Heater Power Supply- 12v
2.00
U
Sensor Signal- 0.1v to 1.1v
3.00
B
Ground
Throttle Position Sensor X171
1
2
3
3way-Black
PIN
WIRE
COLOR
FUNCTION
1.00
RB
Signal Ground
2.00
R
Sensor Signal
3.00
Y
TPS Reference voltage- 5v
13/14CU and 14CUX Systems
103
13/14CU AND 14CUX SYSTEMS
14CUX ECM Tune Summary
Tune
ACpplication
R3652
3.9 litre ‘93-‘95 MY Range Rover Classic
3.9 litre ‘93-‘95 MY Discovery
R3653
4.2 litre ‘93-‘95 MY Range Rover Classic
R3654
3.9 litre ‘94-‘95 MY Defender 90
3.9 litre ‘93 MY Defender 110
R3362
3.9 litre ‘89-‘92 MY Range Rover Classic
Low compression
Note:When using Tune # R3652, R3653, or R3654 to correct cold start complaints, the entire
“Cold Start Enhancement” package must also be used (except Defender 110)
See reverse for complete tune listing.
104
13/14CU AND 14CUX SYSTEMS
Model
Tune #
Description
Range Rover Classic 3.9 Low
CR
R2103
Initial production tune
Range Rover Classic 3.9 Low
CR
R2161
Desensitized OBD, IAC refinements
Range Rover Classic 3.9 Low
CR
R2306
Fixed A/C glitch @ 65 mph (2250rpm); eliminated tune resistor
(Code 21)
Range Rover Classic 3.9 Low
CR
R2419
Desensitized OBD, , prinarily Code 48; Service Actioon (Recall
CA)
Range Rover Classic 3.9 Low
CR
R2665
Improved IAC control, new strategy for IAC OBD; further OBD
desensitization
Range Rover Classic 3.9 High
CR
R2813
Initial production tune
Range Rover Classic 4.2 High
CR
R2926
B
Initial production tune
Defender 3.9 High CR
R3038
Initial production tune
Range Rover Classic 3.9 High
CR
R3100
Low Reed Vapor Pressure fuel tune
Range Rover Classic 4.2 High
CR
R3102
Low Reed Vapor Pressure fuel tune
Range Rover Classic 3.9 High
CR
R3315
MIL on no code fix (interim)
Range Rover Classic 4.2 Low
CR
R3316
MIL on no code fix (interim)
Range Rover Classic 3.9 Low
CR
R3326
Low Reed Vapor Pressure fuel tune (interim)
Range Rover Classic 3.9 Low
CR
R3339
MIL on no code fix (interim)
Defender 3.9 High CR
R3340
MIL on no code fix (interim)
Defender 3.9 High CR
R3341
Low Reed Vapor Pressure fuel tune (interim)
Range Rover Classic 3.9 High
CR
R3342
A
MIL on no code fix (interim)
Range Rover Classic 4.2 High
CR
R3343
A
MIL on no code fix (interim)
Range Rover Classic/ Discovery
3.9 High CR
R3360
Desensitized OBD 95 MY Tune (‘94 Discovery)
Range Rover Classic 4.2
R3361
Desensitized OBD 95 MY Tune
Range Rover Classic 3.9 Low
CR
R3362
Desensitized OBD 95 MY Tune; improvements for Low CR
13/14CU and 14CUX Systems
105
13/14CU AND 14CUX SYSTEMS
Defender 3.9 High CR
R3365
Desensitized OBD 95 MY Tune
Range Rover Classic 4.2
R3507
Part # PRM3361A; Interim improved Cold Start, fueling below 22âC (- 10âF)
Range Rover Classic/Discovery
3.9 High CR
R3526
Part # PRM3360A; Note: LR Part numbers are different from
Tune numbers
Defender 3.9 High CR
R3529
Part # PRM3365A
Range Rover Classic/Discovery
3.9 High CR
R3652
Operation Pride Tune
Range Rover Classic 4.2 High
CR
R3653
Defender 3.9 High CR
R3654
Current tune with final improved Cold Start fueling below -22âC
(-10âF).
Operation Pride Tune
Current tune with final improved Cold Start fueling below -22âC
(-10âF).
Operation Pride Tune
Current tune with final improved Cold Start fueling below -22âC
(-10âF).
106
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
Land Rover moves into the next level of sophistication in engine management with the Generic
Engine Management System (GEMS). GEMS incorporates the function of the distributor into
the ECM to provide a computer-controlled Distributorless Ignition System (DIS).
GEMS also provides more precise fuel delivery through the use of adaptive operating software
and Sequential Multiport Fuel Injection. More sophisticated OBD II diagnostic capabilities are
also included as part of the package.
New default strategies have been incorporated into the GEMS to allow the vehicle to continue
running in the event of sensor failure - sometimes without any apparent symptoms other than
an illuminated MIL. When this is occurring, however, there is a reduction in vehicle
performance, economy, or emissions system operation.
Generic Engine Management System (GEMS)
107
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
ELECTRONIC CONTROL MODULE (ECM)
GEMS Electronic Control Module
System Inputs
The ECM is mounted in the engine compartment. The expanded list of ECM inputs is as
follows:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Crankshaft Position (CKP) Sensor
Ignition Signal (Key on signal)
Camshaft Position (CMP) Sensor
Knock Sensor (KS)
Intake Air Temperature Sensor
Engine Coolant Temperature (ECT) Sensor
Engine Fuel Temperature (EFT) Sensor
Throttle Position Sensor (TPS)
Mass Air Flow Sensor (MAFS)
Park/Neutral Position Switch (PNPS)
Heated Oxygen Sensors (4)
Fuel Level Sensor
Heated Front Screen
Road speed (Range Rover)
Air Conditioning request
Battery Voltage
Cooling fan request
Security link
ABS link
Several of these inputs (road speed, A/C request) originate in the ABS Module and are received
via the Body Control Module.
108
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
System Outputs
System outputs are as follows:
•
•
•
•
•
•
•
•
•
A/C Compressor Clutch
Fan Control
Fuel Injectors
Idle Air Control
Purge Valve
Malfunction Indicator Lamp (MIL)
Fuel Pump Relay
Main Relay
Coil Driver
NEW COMPONENTS
Many system inputs and outputs remain similar previous models. There are, however, several
important exceptions:
Generic Engine Management System (GEMS)
109
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
Mass Air Flow Sensor (MAFS)
GEMS controlled vehicles use a MAFS with somewhat less responsibility than the sensor used
on previous models. The MAFS sensor contains a single heated wire that is used, as on
previous models, to measure air flow. The second wire, used to determine intake air
temperature, is remotely mounted on GEMS vehicles and is no longer a part of the MAFS
function.
Mass Air Flow Sensor
Intake Air Temperature Sensor
A dedicated sensor, mounted on the air cleaner housing, measures intake air temperature.
Intake Air Temperature Sensor
Crankshaft Position (CKP) Sensor
Basic engine timing is controlled by the ECM using input from the crankshaft position sensor.
The sensor's signal is also used by the ECM in its engine knock and cylinder misfire operating
strategies. There are no back-up strategies for the Crankshaft Position Sensor. The engine will
not start or continue to run in the event of a Crankshaft Position Sensor failure.
110
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
The sensor is mounted on the flywheel housing.
Crankshaft Position Sensor
A detailed description of the Crankshaft Position Sensor's signal is provided in the Ignition
System section of this book.
Crankshaft Position Sensor Scope Pattern
Camshaft Position (CMP) Sensor
Camshaft position input is provided to the GEMS by a Hall Effect sensor located on the engine's
front cover. Electronic pulses are produced as lobes on the cam chain wheel pass the sensor
tip. Four pulses are produced for every two engine revolutions.
Generic Engine Management System (GEMS)
111
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
Camshaft Position Sensor
The camshaft position signal is used by the ECM to precisely time fuel injector operation. This
is especially important with SFI. The signal is also used, along with the crankshaft position
sensor, as part of the engine knock control strategy.
A camshaft position sensor was not used on pre-GEMS systems.
Camshaft Position Sensor Scope Pattern
Rear HO2S Sensors
Additional oxygen sensors are mounted in the exhaust system, downstream from each of the
vehicle's catalytic converters. Data from these new sensors is compared with the signal
produced by the front sensor on each bank. This information is used by the GEMS to monitor
performance of the Three-Way Catalyst (TWC).
The rear sensors are also part of the ECM's fuel system back-up strategy. Should the signal
from the front HO2S fail, the signal from the corresponding rear sensor will be used so that the
vehicle can remain in closed-loop operation.
112
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
Oxygen Sensor Circuit
Inertia Switch
The inertia switch on GEMS equipped vehicles has been relocated to the passenger
compartment, behind a trim panel on the right side footwell. Operation is identical to that of
previous models.
Inertia Switch
Ignition Coils
New ignition coils are used as part of the GEMS controlled Distributorless Ignition System
(DIS). Four double-ended coils are mounted on a bracket at the rear of the engine
compartment.
The circuit for each coil is completed by switching within the ECM. This produces sparks in two
cylinders simultaneously, one cylinder on the compression stroke and one on the exhaust
stroke. The spark on the exhaust stroke is the "wasted" spark described in the Ignition section
of this book.
Generic Engine Management System (GEMS)
113
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
The ECM provides precise coil operation and ignition timing based on inputs including cam and
crank position, coolant temperature, engine knock and load.
Range Rover SE Ignition Coils
Relays
The GEMS engine management system uses four relays:
•
•
•
•
Main Relay
Ignition Relay
Starter Motor Relay
Fuel Pump Relay
Each of these relays is located in a fuse box mounted in the engine compartment.
The main relay supplies power to the ECM, fuel injectors, mass air flow meter and purge valve.
Failure of this relay will prevent the engine from starting.
The ignition relay supplies power to the coils, fuel pump relay and heated oxygen sensors. This
relay is immediately de-energized when the ignition key is turned to the OFF position.
The starter relay provides the power feed to the starter motor. Operation of this relay is
controlled by the ignition key.
114
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
The fuel pump relay is powered through the ignition relay and controlled by the ECM. The relay
is first activated briefly with the key in the ON position to prime the fuel system. The relay
remains activated during cranking and while the engine is running.
Relay Location in Fuse Box
Generic Engine Management System (GEMS)
115
GENERIC ENGINE MANAGEMENT SYSTEM (GEMS)
116
GEMS CONNECTOR PINOUTS
GEMS CONNECTOR PINOUTS
Range Rover 4.0/4.6
C505 (36way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
BG
A/C Clutch Control via HEVAC
ECU
19
SY
Purge Control Valve Control
2
GU
Fuel Consumption output to computer
20
-
3
P
Cooling Fan Relay
21
WO
HO2S Upstream Heater Control
4
-
22
BY
MIL control via BeCM
5
-
23
S
Engine speed output to BeCM
6
-
24
UP
Fuel Pump Relay Control
7
-
25
-
8
-
26
-
9
-
27
YO
Throttle Angle Output to TCU
10
-
28
WU
HO2S Downstream Heater Control
11
YB
29
SP
Engine Torque Output to TCU
12
-
30
YN
Cylinder #4 Injector Control
13
YU
31
-
14
-
32
YR
Cylinder #7 Injector Control
15
US
IACV-D
33
YG
Cylinder #5 Injector Control
16
RG
IACV-B
34
GW
IACV-C
17
YS
Cylinder #6 Injector Control
35
OR
IACV-A
18
YK
Cylinder #8 Injector Control
36
YW
Cylinder #2 Injector Control
Cylinder #3 Injector Control
Cylinder #1 Injector Control
GEMS Connector Pinouts
117
GEMS CONNECTOR PINOUTS
Range Rover 4.0/4.6
C507 (36way-Red)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
1
YK
ABS Rough Road input (96MY)
19
-
2
SU
Cam Position Sensor
20
-
Data Link (non-NAS)
3
-
21
PG
Heated Front Screen input
4
ULG
22
-
5
-
23
KR
6
-
24
-
7
GB
Fuel Level Input
25
-
8
G
Right Downstream HO2S input
26
B
BeCM Engine Immobilization input
9
-
27
Y
Road speed input from ABS ECU
10
RB
Knock Sensor Common (0 volt)
28
BS
A/C Request from HEVAC input
11
KW
LH Knock Sensor input
29
YB
Cooling Fan Request input
12
KB
RH Knock Sensor input
30
-
13
SLG
Air Temperature input
31
SR
Auto Gearbox Ignition retard
14
G
Coolant Temperature Sensor input
32
RB
HO2S Common
15
YLG
Throttle Position Sensor input
33
U
Right Upstream HO2S input
16
UG
Mass Air Flow Sensor input
34
O
Left Upstream HO2S input
17
Y
Left Downstream HO2S input
35
SW
Fuel Temperature Sensor input
18
BO
Park/Neutral Switch input
36
RB
Sensor common
118
T-Box Low Range input (96MY)
FUNCTION
Data Link (NAS)
GEMS CONNECTOR PINOUTS
Range Rover 4.0/4.6
C509 (18way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
WK
Coil Driver Cylinders 5 & 8
10
B
Earth E529
2
-
11
BY
Crank Sensor Negative
3
-
12
KB
Crank Sensor Positive
4
R
TPS 5 volt supply
13
WU
Coil Drivers Cylinders 2&3
5
B
Earth E529
14
WB
Coil Drivers Cylinders 1&6
6
-
15
WY
Coil Drivers Cylinders 4&7
7
NO
Power Supply from Main Relay
16
B
Earth E529
8
W
“ON” input from Ignition Relay
17
UR
Main Relay Control - Low output
9
B
Earth E 529
18
-
Heated Oxygen Sensors (HO2S)
C521 Left Upstream
C526 Right Upstream
C535 Left Downstream
C536 Right Downstream
(4-way, Black)
PIN
Wire Color
Description
C521
C526
C535
C536
Left
Upstream
Right Upstream
Left
Downstream
Right
Downstream
1
O
U
Y
G
HO2S 5 Volt Reference
2
RB
RB
RB
RB
HO2S Signal Ground
GEMS Connector Pinouts
119
GEMS CONNECTOR PINOUTS
3
W
W
W
W
Heater Power supply
4
WO
WO
WU
WU
Heater Control
Data Link Connector (X-318)
C231 (16-way, Black)
120
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
1
SR
Air Suspension Reset
9
-
2
-
10
-
3
-
11
WLG
“K”-Air Suspension
4
B
Battery Negative
12
WK
“L”-Air Suspension
5
BP
Chassis Negative
13
YK
“K”-SRS
6
-
14
YG
“L”-SRS
7
KR
15
LGR
“L”-GEMS,BeCM,HVAC,ABS
8
-
16
N
Battery Positive(F33-Underhood)
“K”-GEMS,BeCM,HVAC,ABS
FUNCTION
GEMS CONNECTOR PINOUTS
Discovery without EVAPS [pre 97MY]
C1032 (36way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
BS
A/C Clutch Relay Control
19
SY
Purge Control Valve Control
2
-
20
-
3
GW
21
WO
HO2S Upstream Heater Control
4
-
22
RS
MIL control
5
-
23
-
6
-
24
UP
7
-
25
-
8
-
26
-
9
-
27
-
10
-
28
WU
11
YB
29
-
12
-
30
YN
13
YU
31
-
14
-
32
YR
Cylinder #7 Injector Control
15
US
IACV-D
33
YG
Cylinder #5 Injector Control
16
RG
IACV-B
34
GW
IACV-C
17
YS
Cylinder #6 Injector Control
35
OR
IACV-A
18
YK
Cylinder #8 Injector Control
36
YW
Cylinder #2 Injector Control
Cooling Fan Relay Control
Cylinder #3 Injector Control
Cylinder #1 Injector Control
GEMS Connector Pinouts
Fuel Pump Relay Control
HO2S Downstream Heater Control
Cylinder #4 Injector Control
121
GEMS CONNECTOR PINOUTS
Discovery without EVAPS [pre-97MY]
C1017 (36way-Red)
122
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
YK
ABS Rough Road input (96MY)
19
-
2
SU
Cam Position Sensor
20
WK
3
-
21
-
4
-
22
-
5
-
23
WLG
6
-
24
-
7
GB
Fuel Level Input
25
-
8
R
Right Downstream HO2S input
26
B
10AS Engine Immobilization input
9
-
27
YK
Road speed input from ABS ECU
10
RB
Knock Sensor Common (0 volt)
28
YB
A/C Request input
11
O
LH Knock Sensor input
29
PB
Cooling Fan Request input
12
Y
RH Knock Sensor input
30
-
13
SLG
Air Temperature input
31
-
14
G
Coolant Temperature Sensor input
32
RB
HO2S Common
15
YLG
Throttle Position Sensor input
33
OG
Right Upstream HO2S input
16
UG
Mass Air Flow Sensor input
34
GR
Left Upstream HO2S input
17
GW
Left Downstream HO2S input
35
SW
Fuel Temperature Sensor input
18
OB
Park/Neutral Switch input
36
RB
Sensor common
Data Link (non-NAS)
Data Link (NAS)
GEMS CONNECTOR PINOUTS
Discovery without EVAPS [pre-97MY]
C1033 (18way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
WK
Coil Driver Cylinders 5 & 8
10
B
Earth E529
2
-
11
G
Crank Sensor Negative
3
-
12
N
Crank Sensor Positive
4
R
TPS 5 volt supply
13
WU
Coil Drivers Cylinders 2&3
5
B
Earth E529
14
WB
Coil Drivers Cylinders 1&6
6
-
15
WY
Coil Drivers Cylinders 4&7
7
NO
Power Supply from Main Relay
16
B
Earth E529
8
G
“ON” input from Ignition Relay
17
UR
Main Relay Control - Low output
9
B
Earth E 529
18
-
Heated Oxygen Sensors (HO2S)
C112 Left Upstream
C113 Right Upstream
C1019 Left Downstream
C1020 Right Downstream
(4-way, Black)
PIN
Wire Color
Description
C112
Left
Upstream
C113
Right
Upstream
C1019
Left
Downstream
C1020
Right
Downstream
1
UY/GR
OG
GW
R
HO2S 5 Volt Reference
2
UW/NU
YB
NW
U
HO2S Signal Ground
3
B/WG
WG
WG
WG
Heater Power supply
GEMS Connector Pinouts
123
GEMS CONNECTOR PINOUTS
4
NU/WO
WO
WU
WU
Heater Control
MULTI-FUNCTION RELAY UNIT CONNECTORS
Discovery (without EVAPS) C1029 (8way-Black)
PIN
WIRE
COLOR
FUNCTION
1
-
2
-
3
NO
Load Relay power out to ECM, Injectors, CANPV, MAFS, CMP
4
WP
Fuel Pump Power out
5
-
6
NLG
Battery power to Load relay from
Fuse F7
7
PW
Battery power to Fuel Pump Relay
Fuse F6
8
NO
Load Relay power out common with
pin 3
Discovery (without EVAPS) C1030 (6way-Black)
124
PIN
WIRE
COLOR
FUNCTION
1
UP
Fuel Pump Relay control from ECM
2
WG
Key on power Fuel Pump Relay control from Fuse F3
3
UR
Main Relay control from ECM
4
-
5
-
6
-
GEMS CONNECTOR PINOUTS
Discovery with EVAPS [97-99½ MY]
C1032 (36way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
BS
A/C Clutch Relay Control
19
SY
Purge Control Valve Control
2
-
20
-
3
GW
21
WO
HO2S Upstream Heater Control
4
-
22
RS
MIL control
5
-
23
-
6
NR
24
UP
7
-
25
-
8
-
26
-
9
-
27
-
10
-
28
WU
11
YB
29
-
12
-
30
YN
13
YU
31
-
14
-
32
YR
Cylinder #7 Injector Control
15
US
IACV-D
33
YG
Cylinder #5 Injector Control
16
RG
IACV-B
34
GW
IACV-C
17
YS
Cylinder #6 Injector Control
35
OR
IACV-A
18
YK
Cylinder #8 Injector Control
36
YW
Cylinder #2 Injector Control
Cooling Fan Relay Control
Canister Vent Seal Valve
control
Cylinder #3 Injector Control
Cylinder #1 Injector Control
GEMS Connector Pinouts
Fuel Pump Relay Control
HO2S Downstream Heater Control
Cylinder #4 Injector Control
125
GEMS CONNECTOR PINOUTS
Discovery with EVAPS [97-99½ MY]
C1017 (36way-Red)
126
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
YK
ABS Rough Road input (96MY)
19
-
2
SU
Cam Position Sensor
20
WK
3
-
21
-
4
-
22
-
5
-
23
WLG
6
-
24
-
7
GB
Fuel Level Input
25
-
8
R
Right Downstream HO2S input
26
B
10AS Engine Immobilization input
9
-
27
YK
Road speed input from ABS ECU
10
RB
Knock Sensor Common (0 volt)
28
YB
A/C Request input
11
O
LH Knock Sensor input
29
PB
Cooling Fan Request input
12
Y
RH Knock Sensor input
30
GK
Fuel Tank Pressure input
13
SLG
Air Temperature input
31
-
14
G
Coolant Temperature Sensor input
32
RB
HO2S Common
15
YLG
Throttle Position Sensor input
33
OG
Right Upstream HO2S input
16
UG
Mass Air Flow Sensor input
34
GR
Left Upstream HO2S input
17
GW
Left Downstream HO2S input
35
SW
Fuel Temperature Sensor input
18
OB
Park/Neutral Switch input
36
RB
Sensor common
Data Link (non-NAS)
Data Link (NAS)
GEMS CONNECTOR PINOUTS
Discovery with EVAPS [97-99½ MY]
C1033 (18way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
WK
Coil Driver Cylinders 5 & 8
10
B
Earth E529
2
-
11
G
Crank Sensor Negative
3
-
12
N
Crank Sensor Positive
4
R
TPS 5 volt supply
13
WU
Coil Drivers Cylinders 2&3
5
B
Earth E529
14
WB
Coil Drivers Cylinders 1&6
6
-
15
WY
Coil Drivers Cylinders 4&7
7
NO
Power Supply from Main Relay
16
B
Earth E529
8
G
“ON” input from Ignition Relay
17
UR
Main Relay Control - Low output
9
B
Earth E 529
18
-
Heated Oxygen Sensors (HO2S)
C112 Left Upstream
C113 Right Upstream
GEMS Connector Pinouts
127
GEMS CONNECTOR PINOUTS
C1019 Left Downstream
C1020 Right Downstream
(4-way, Black)
PIN
Wire Color
Description
C112
C113
C1019
C1020
Left
Upstream
Right
Upstream
Left
Downstream
Right
Downstream
1
UY/GR
OG
GW
R
HO2S 5 Volt Reference
2
UW/NU
YB
NW
U
HO2S Signal Ground
3
B/WG
WG
WG
WG
Heater Power supply
4
NU/WO
WO
WU
WU
Heater Control
MULTI-FUNCTION RELAY UNIT CONNECTORS
Discovery (with EVAPS)[97-99½ MY]
C1029 (8way-Black)
PIN
WIRE
COLOR
FUNCTION
1
-
2
-
3
NO
Load Relay power out to ECM, Injectors, CANPV, MAFS, CMP
4
WP
Fuel Pump Power out
5
-
6
NLG
Battery power to Load relay from Fuse F7
7
PW
Battery power to Fuel Pump Relay Fuse F6
8
NO
Load Relay power out common with pin 3
Discovery (with EVAPS)[97-99½ MY]
128
GEMS CONNECTOR PINOUTS
C1030 (6way-Black)
PIN
WIRE
COLOR
FUNCTION
1
UP
Fuel Pump Relay control from ECM
2
WG
Key on power Fuel Pump Relay control from Fuse F3
3
UR
Main Relay control from ECM
4
-
5
-
6
-
Data Link Connector (X-318)
Discovery (All with GEMS) C2083 (16-way, Black)
PIN
WIRE
COLOR
1
PIN
WIRE
COLOR
-
9
-
2
-
10
-
3
-
11
-
4
B
Battery Negative
12
-
5
B
Chassis Negative
13
YK
“K”-SRS
6
-
7
WLG
“K”-GEMS,,ABS
15
WK
“L”-GEMS, ABS
8
KB
“K”-10AS
16
WR
Battery Positive
(F3-Satellite Box2)
GEMS Connector Pinouts
FUNCTION
FUNCTION
14
129
GEMS CONNECTOR PINOUTS
1997 Defender 90
C634 (36way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
BS
A/C Clutch Relay enable (-)
19
SY
Purge Control Valve enable (-)
2
-
20
-
3
GW
21
WO
HO2S Upstream Heater Control
4
-
22
RS
MIL bulb and Immob. ECU (Output)
5
-
23
-
6
-
24
UP
7
-
25
-
8
-
26
-
9
-
27
-
10
-
28
WU
11
YB
29
-
12
-
30
YN
13
YU
31
-
14
-
32
YR
Cylinder #7 Injector Control
15
US
IACV-D
33
YG
Cylinder #5 Injector Control
16
RG
IACV-B
34
GW
IACV-C
17
YS
Cylinder #6 Injector Control
35
OR
IACV-A
18
YK
Cylinder #8 Injector Control
36
YW
Cylinder #2 Injector Control
130
Cooling Fan Relay enable (-)
Cylinder #3 Injector Control
Cylinder #1 Injector Control
Fuel Pump Relay Control (+)
HO2S Downstream Heater Control
Cylinder #4 Injector Control
GEMS CONNECTOR PINOUTS
1997 Defender 90
C636 (36way-Red)
PIN
WIRE
COLOR
FUNCTION
PIN
1
YR
ROUGH ROAD DET. ECU
19
2
SU
CMP SENSOR INPUT
20
3
21
4
22
5
23
6
24
WIRE
COLOR
FUNCTION
WK
ROUGH ROAD DET. ECU
WLG
ROUGH ROAD DET. ECU
Immobilization Unit Input
7
GB
FUEL LEVEL INPUT
25
8
R
R.R. O2 SENSOR INPUT
26
B
27
YK
9
10
RB
KNOCK SENSOR GROUND
28
YB
A.C. COMPRESSOR REQUEST
(TRINARY
SWITCH
-HIGH/LOW
PRESS.)
11
O
L. KNOCK SENSOR
29
PB
A.C. CONDSER FAN REQUEST
(A.C. TRINARY SWITCH -MED.
PRESS.)
12
Y
R. KNOCK SENSOR INPUT
30
13
SLG
AIR TEMP SENSOR INPUT
31
14
G
ECT SENSOR INPUT
32
RB
O2 SENSOR GROUND
15
YLG
TP SENSOR INPUT
33
OG
R.F. O2 SENSOR INPUT
16
UG
MAF SENSOR INPUT
34
GR
L.F. O2 SENSOR INPUT
17
GW
L.R. O2 SENSOR INPUT
35
SW
FUEL TEMP SENSOR INPUT
18
OB
STARTER RELAY GROUND
36
RB
MULT.* SENSOR GROUND
* Multiple Sensor Ground= TP, ECT, MAF, CMP, Fuel Temp., Air Temp.
GEMS Connector Pinouts
131
GEMS CONNECTOR PINOUTS
1997 Defender 90
C635 (18way-Black)
PIN
WIRE
COLOR
FUNCTION
PIN
WIRE
COLOR
FUNCTION
1
WK
Coil Driver Cylinders 5 & 8
10
B
Earth C560
2
-
11
G
Crank Sensor Negative
3
-
12
N
Crank Sensor Positive
4
R
TPS 5 volt supply
13
WU
Coil Drivers Cylinders 2&3
5
B
Earth C560
14
WB
Coil Drivers Cylinders 1&6
6
-
15
WY
Coil Drivers Cylinders 4&7
7
NO
Power Supply from Main Relay
16
B
Earth C560
8
WG
Fuel Pump Relay enable (-)
17
UR
Main Relay Control - enable (-)
9
B
Earth C560
18
-
Heated Oxygen Sensors (HO2S)
C644 Left Upstream
C645 Right Upstream
132
GEMS CONNECTOR PINOUTS
C643 Left Downstream
C642 Right Downstream
(4-way, Black)
PIN
Wire Color
Description
C644
Left
Upstream
C645
Right
stream
C643
Left
Downstream
C642
Right
Downstream
1
O
U
Y
G
HO2S 5 Volt Reference
2
RB
RB
RB
RB
HO2S Signal Ground
3
W
W
W
W
Heater Power supply
4
WO
WO
WU
WU
Heater Control
Up-
Data Link Connector (X-318)
C040 (16-way, Black)
PIN
WIRE
COLOR
1
FUNCTION
PIN
WIRE
COLOR
-
9
-
2
-
10
-
3
-
11
-
4
B
Chassis Negative (Header C286,
C550)
12
-
5
B
Chassis Negative (Header C286,
C550)
13
-
6
-
14
-
7
WLG
15
WK
“L”-GEMS, Rough Road Det. ECU
8
OLG
16
P
Battery Positive(Fuse 3-Passenger Compartment)
“K”-GEMS, Rough Road Det. ECU
GEMS Connector Pinouts
FUNCTION
133
GEMS CONNECTOR PINOUTS
134
GEMS ECM TUNE SUMMARY
GEMS ECM TUNE SUMMARY
NOTE: Any of the following tune levels may be valid for the year/model listed. ECM tunes
should only be changed according to published service documentation or at the direction of the
Technical Help desk, and only due to verified complaint or symptoms. Should a replacement be
necessary, only 'Final Service Fix' PROM's should be used unless otherwise directed by
Techline.
Model
Tune #
Description
95MY RR
9612
Production Tune, POE installed.
9613
Production Tune, Line Build.
9638
“Final" Service fix
9618
Original Production Tune
9622
Service Fix for ABS/T-box Link Faults (P1317/1703)
9636
“Final" Service fix
97MY RR
9635
POE fix for Oxy period fix on 4.6L
9639
“Final" Service fix
98MY RR
9648
Original Production Tune (Contains all RR final service fixes)
99MY RR
9648
Original Production Tune (same as 98 MY)
99MY Calloway
9659
Available only with complete ECM
96MY Discovery
9621
Orignial Production Tune - phase 1
9623
Orignial Production Tune - phase 2
9631
Service Fix for ABS Link P1317 and Warm up timer P0125 (both phase 1&2)
9637
“Final" Service fix - Auto trans
96MY RR
97MY Discovery
9630
“Final" Service fix - Man trans
9624
Original Production Tune - Auto trans
9629
Original Production Tune - Man trans
9662
“Final" Service fix - Auto trans
9644
“Final" Service fix - Man trans
9633
Original Production Tune - Auto trans
9634
Original Production Tune - Man trans
9640
Running change, fix for Idle Surge and Fuel Level Fault P0461
9641
Running change, fix for Idle Surge and Fuel Level Fault P0461
9652
“Final" Service fix - Auto trans
9653
“Final" Service fix - Man trans
98MY Discovery
9652
Original Production Tune - Auto trans (Contains all 97 Discovery final service fixes)
9655
“Final" Service fix - Auto trans
99MYDisco
9655
Original Production Tune - Auto trans (same as 98 MY)
97MY Def 90
9632
Original Production Tune
9661
“Final" Service fix
97.5MY Discovery w/
EVAP Leak Detection
Range Rover “Final" Service fix tunes will include: Oxy period resolution to driver induced faults, Idle speed improvement
preventing cold hesitation, and Engine Speed Fault (Gbox 21). Improved torque map to prevent Torque Reduction Fault
(Gbox 23).
Discovery “Final" Service fix tunes will include: Oxy period resolution to driver induced faults, Trailing Throttle Misfire, Idle
speed improvement preventing cold hesitation, Idle speed fluctuation on decel, Fuel Level Fault P0461.
GEMS ECM Tune Summary
135
GEMS ECM TUNE SUMMARY
Interim Service Tunes
The following is a list of unreleased tunes that were sent out by the GEMS Helpline on a case
by case basis to correct individual problems.
Each one contains elements of the final service fix, but does not provide the full benefit of a final
service fix tune.
Model
Tune #
Description
95 MY RR
4000
Increased Idle speed, Oxy Period fix (P0130/0150)
96 MY RR
4001
Increased Idle speed, Oxy Period fix (P0130/0150)
97 MY RR
4002
Increased Idle speed, Oxy Period fix (P0130/0150)
96 MY Discovery
8173
Increased Idle speed.
96 MY Discovery
568_563
Misfire trailing throttle and Oxy period fix (P0130/0150)
Other Tunes
The following is a list of tunes that may be encountered in a vehicle, but are not appropriate for
the year/model listed.
Model
Tune #
Description
95MY RR
9601
Original Production Tune - never sold
97MY RR
9626
Original Production Tune (All reworked to 9635)
98MY Discovery
9653
Original Production Tune - Man trans (no NAS Man trans built)
136
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Introduction
Bosch supplies the engine management system used on Discovery Series II and Range Rover
beginning mid 1999 model year. It is referred to as the Bosch Motronic 5.2.1 system. The
system supports sequential fuel injection and waste spark ignition. The system is designed to
optimize the performance and efficiency of the engine.
The key functions of the Bosch 5.2.1 engine management system are:
•
•
•
•
•
•
•
•
•
To control the amount of fuel supplied to each cylinder
To calculate and control the exact point of fuel injection
To calculate and control the exact point of ignition on each cylinder
To optimize adjustment of the injection and ignition timings to deliver the maximum engine
performance throughout all engine speed and load conditions
To calculate and maintain the desired air/fuel ratio, to ensure the 3 way catalysts operate at
their maximum efficiency
To maintain full idle speed control of the engine
To ensure the vehicle adheres to the emission standards
To ensure the vehicle meets with the fault handling requirements, as detailed in the ‘Onboard diagnostic II’ (OBDII) legislation
To provide an interface with other electrical systems on the vehicle
To deliver these key functions, the Bosch 5.2.1 engine management system relies upon a
number of inputs and controls a number of outputs. As with all electronic control units, the ECM
needs information regarding the current operating conditions of the engine and other related
systems before it can make calculations, which determine the appropriate outputs.
Bosch 5.2.1 Engine Management System
137
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
System Components
138
1.
Mass Airflow & Temperature
Sensor
8.
Idle Air Control Valve
2.
Fuel Injectors
9.
Ignition Coils
3.
Spark Plugs/High Tension Leads
10.
Engine Coolant Temperature
Sensor
4.
Fuel Pump Relay
11.
Crankshaft Speed and Position
Sensor
5.
A/C Compressor Clutch & Cooling Fan Relay
12.
Knock Sensor
6.
Throttle Position Sensor
13.
Camshaft Position Sensor
7.
Heated Oxygen Sensor
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
System Inputs
The Bosch 5.2.1 system optimizes engine performance by interpreting signals from numerous
vehicle sensors and other inputs. Some of these signals are produced by the actions of the
driver, some are supplied by sensors located on and around the engine and some are supplied
by other vehicle systems.
The inputs are as follows:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ignition switch (position II)
Throttle position sensor (TPS)
Crankshaft position sensor (CKP)
Camshaft position sensor (CMP)
Engine coolant temperature sensor (ECT)
Knock sensors (KS)
Air mass flow and temperature sensor (MAF)
Heated Oxygen sensors (HO2)
Immobilization signal
Fuel level signal
Vehicle speed sensor (VSS)
Rough road detection signal
Automatic temperature control (ATC) system request
Automatic gearbox information
Fuel tank pressure sensor
Engine control module
The engine control module (ECM) is secured to a pressed steel bracket located at dash level on
the right hand ‘A’ post. It features five separate electrical connectors. Each connector groups
associated pin-outs together.
The five connectors interlock when connected to the ECM. Therefore, they must be connected
to the ECM in a specific order. Connector 1 must be used first, connector 2 second, connector 3
third, and so on. The connectors can be disconnected only in the reverse order of this. It is not
possible to remove the connectors from the ECM in any other order, the way in which the
connectors interlock prevents this.
The main functions of the groups of pin outs incorporated into each connector are detailed in
the following table.
Connector
number
Connector
color
Main functions
1
Black
Main power supply and ground connections
2
Black
Oxygen sensor inputs and Oxygen sensor
3
Black
All sensor inputs and outputs
Bosch 5.2.1 Engine Management System
139
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
4
Black
Most related vehicle system communications.
5
Black
Ignition coil control
The ECM is programmed during manufacture by writing the program and the engine ‘tune’ into
the Flash EPROM (erasable programmable read only memory). This Flash EPROM can be
reprogrammed in service, using TestBook. In certain circumstances, it is possible to alter the
‘tune’ or functionality of the ECM using this process.
The engine management system (EMS) now used on Discovery Series II , is an improvement
over existing systems. The new EMS now improves the capability with respect to the
monitoring, evaluating, diagnosing and correcting of many engine mechanical irregularities. It
also has improved capability for monitoring and adapting its own operation to ensure that any
mechanical variations do not affect the performance or the exhaust emissions of the engine.
The ECM has advanced fault-handling capabilities. It can detect the type and severity of faults,
store relevant engine operating conditions at the time a fault occurs and also store the time the
fault occurred. The individual fault handling procedures the ECM completes will be explained
throughout the section. The ECM stores fault codes, referred to as ‘P’ codes. It is this ‘P’ code
that Land Rover has to make available to third party scanning tools. The ‘P’ codes are defined
within the OBDII legislation. Three environment variables are stored for each fault, in addition to
Freeze Frame data. Once recorded, details of a fault will stay in the ECM’s memory for 40
‘trips’.
A ‘trip’ is defined precisely by the on board diagnostic (OBD) legislation. It is a predetermined
routine through which the engine or vehicle must pass before the ECM will attempt to ‘validate’
a previously faulty signal. There are a number of OBD set routines. They are all grouped into
one of several inspection/maintenance flags (IMF). These are:
•
•
•
•
Catalytic converter efficiency
Purge (all markets) / evaporative emission leak detection diagnostic.
Oxygen sensor diagnostics
Oxygen sensor heater diagnostics
The above diagnostics all demand very strict engine conditions be met before they will run. By
following the appropriate driving cycle, the IMF flags will indicate when the diagnostic
completes. Most of the other diagnostics will operate within the first 30 seconds after engine
starts. Refer to the appropriate service literature for details on drive cycle, trip, and journey
details for any given sensor/system.
TestBook can be used to view the diagnostic routines performed by the ECM, which need to be
set before the relevant IMF becomes set. When a fault code is stored, it will indicate, via
TestBook, the IMF required to ensure that successful repair can been verified.
When certain fault conditions prevail, the EMS stores data relating to the value of certain engine
inputs. These values, when stored, are known as ‘freeze frame data’. Freeze frame data is not
the same as the three environmental variables stored when a fault is detected. Environmental
variables are stored along with each fault (three variable conditions for each ‘P’ code), whereas
freeze frame data is stored for the highest priority fault (different faults have different priorities,
according to their likely impact on exhaust gas emissions).
140
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Freeze frame data always records:
•
•
•
•
•
•
•
•
Engine speed
Engine load
‘P’ code
Short term fuelling trim A / B
Long term fuelling trim A / B
Fuelling status A / B
Coolant temp
Road speed
The ECM will illuminate the malfunction indicator lamp (MIL) on detection of a fault, providing
the fault has occurred on two consecutive driving cycles. This strategy ‘validates’ the fault,
ensuring that the MIL does not illuminate needlessly. There is one exception to this, this being
the ECM detecting that a catalyst-damaging misfire is currently occurring. In this case, the ECM
will flash the MIL immediately the fault is detected. If the fault rectifies itself, the ECM will stop
flashing the MIL, changing it to continuously ‘on’.
The MIL is illuminated by a bulb check facility when the ignition is switched to position II, a “MIL
event fault”, or if the automatic gearbox requests it.
Ignition switch
The ignition switch supplies a signal to the ECM whenever it is turned to position II (‘ignition
on’). Using this signal, the ECM is able to detect when the ignition switch is turned ‘on’ and
when it is turned ‘off’. The ECM will initiate its ‘power-up’ sequence whenever the ignition is
turned ‘on’. At this time it will energize the main relay (which, amongst other things, supplies the
main feed to the ECM), energize the fuel pump relay and initiate a ‘self-check’ on the EMS
system.
When it detects the ignition switch has been turned ‘off’, the ECM will stop the engine (if it was
running) and record all the relevant information within its internal memory to enable the quickstart functions to operate correctly. It will then initiate its ‘power-down’ sequence, which involves
de-energizing the main relay.
Throttle position sensor
The throttle position sensor (TPS) is connected to the
throttle valve shaft, located on the throttle body portion of
the plenum chamber (see figure 50). It monitors the
position and the rate of movement of the throttle valve,
which is controlled by the driver via the throttle pedal and
accelerator cable.
Bosch 5.2.1 Engine Management System
141
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The throttle position sensor is a potentiometer. It receives a 5 volt supply from the ECM
whenever the ignition switch is turned ‘on’. It then returns a proportion of the supplied voltage to
the ECM to indicate its position and rate of movement. The actual position of the throttle valve,
the direction in which it is moving (if it is moving) and, if so, the rate at which it is moving will
determine the value of the voltage returned. The returned voltage will be in the range of 0.1
volts (throttle fully closed) to 4.8 volts (throttle fully open). The ECM will supply 5 volts on the
signal wire when the throttle potentiometer is disconnected. This voltage is used in the
diagnostics of the wiring harness. The sensor has gold plated terminals to reduce the
environmental impact. Care must be taken not to scratch the gold coating, particularly when
using a multimeter connected directly to the sensor.
In addition to using the signal supplied by the throttle position sensor to determine the driver’s
requirements, the ECM also uses the signal to check the plausibility of the signal supplied by
the air flow meter. In circumstances where the signal supplied by the air flow meter indicates
that only a small quantity of air is entering the engine, and the signal supplied by the throttle
position sensor indicates a large throttle angle (i.e. throttle open), the ECM will store a ‘ratio
fault’ indicating the throttle position and airflow have not matched.
The TPS sensor does not require any type of adjustment or calibration process. The Bosch
5.2.1 ECM is able to ‘learn’ the closed throttle position using the signal it supplies. If the ECM
detects a sensor failure, or the signal supplied by the throttle position sensor is deemed
implausible, then it will introduce a substitute signal. The actual value of the substitute signal will
be dependent upon a variety of signals received from other sensors located on and around the
engine. Engine performance will be affected in these circumstances and the driver will notice
the following:
•
•
•
•
•
The engine will idle poorly
The vehicle will default to 3rd / 4th gear (limp home strategy automatic vehicles only)
The engine will run poorly and respond poorly to throttle pedal movement
The gearbox will not kickdown (automatic vehicles only)
Altitude adaptations will be incorrect (engine performance affected even more when the
vehicle is operated at high altitudes
Expected Values
Throttle
Angle
Max/Min
Value
Nominal
Value
Diagnostic
Fault Value
Nominal
Resistance
Closed
0.811 mV
0.894 mV
0.960 mV
1.013kW
Fully
Open
0.162 mV
0.096 mV
0.040 mV
2.575kW
TestBook will retrieve the fault code and perform the necessary diagnostics. The sensor can
also be probed directly, providing the care point mentioned above is adhered to. TestBook also
has the capability of displaying the value of the TPS signal received by the ECM. It displays this
on the ‘live reading’ screen. It will also display the altitude adaptive value currently being used
on this screen.
142
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Crankshaft position sensor
The crankshaft position sensor is located in the engine
block, just below number 7 cylinder (see figure 51). It
protrudes through the cylinder block and is positioned
adjacent to the face of the flywheel or flex plate. The
sensor reacts to a ‘drilled reluctor’ incorporated into the
flex plate to ascertain engine speed and position
information. The sensor is located on a spacer and is
secured in position by a single bolt. The spacer is 18 mm
(0.709 in) thick on vehicles used with automatic
transmission. The thickness of the spacer determines
how far the sensor protrudes through the cylinder block
and, therefore, sets the position of the sensor in relation
to the flywheel or flex plate. The sensor and the spacer
are covered by a protective heat shield. The sensor has
three wires attached to it; one signal wire, one ground wire connected to the ECM and one
ground wire connected to vehicle ground. This last wire acts as a shield to earth any stray
electromagnetic radiation produced from the crankshaft signal.
Bosch 5.2.1 Engine Management System
143
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The crankshaft sensor is an inductive type sensor which produces a sinusoidal output voltage
signal. The following illustration shows a typical crankshaft signal over a 480° crankshaft
revolution. This voltage is induced by the proximity of the moving toothed reluctor, which excites
the magnetic flux around the tip of the sensor when each tooth passes. This output voltage will
increase in magnitude and frequency as the engine rpm rises and the speed at which the
reluctor passes the sensor increases. The signal voltage will peak at approximately 6.5 volts if
connected to the ECM (further increases in engine speed will not result in greater magnitude).
The ECM neither specifically monitors nor reacts to the output voltage (unless it is very small or
very large) but does measure the time intervals between each pulse (i.e. signal frequency). The
signal is determined by the number of teeth passing the sensor, and the speed at which they
pass. The teeth are spaced at 6° intervals, with two teeth missing at 60° BTDC to give the ECM
a hardware point of reference, so there is a total of 58 teeth.
The ECM outputs an engine speed signal to the automatic gearbox, the SLABS ECU, the
instrument pack and the ACE ECU. The signal to the automatic gearbox TCM and the SLABS
ECU are supplied via the CAN link, while the signals to the ACE ECU and the instrument pack
are carried via a frequency dependent digital signal.
The signal produced by the crankshaft position sensor is critical to engine running. There is no
backup strategy for this sensor and failure of the signal will result in the engine stalling and/or
failing to start. If the sensor fails when the engine is running, then the engine will stall, a fault
code will be stored and details captured, of the battery voltage, coolant temperature and air
temperature at the time of the failure. If the signal fails when the engine is cranking, then the
engine will not start and no fault will be stored, as the ECM will not detect that an attempt had
been made to start the engine. In both cases the tachometer will also cease to function
immediately and the MIL lamp will not extinguish.
During the power-down procedure, which occurs when the ignition is switched ‘off’, the ECM
stores details of the position of the crankshaft. This enables the ECM to operate the injectors
appropriately to aid quick engine start, which serves to reduce emissions when the engine is
cold.
144
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Camshaft position sensor
The camshaft position sensor is located in the timing cover and the tip of the sensor is
positioned in close proximity to the camshaft gear. The camshaft gear incorporates four teeth.
The camshaft position sensor is a hall-effect sensor which switches a battery fed supply ‘on’
and ‘off’. The supply is switched when the teeth machined onto the camshaft gear pass by the
tip of the sensor. The four teeth are of differing shapes, so the ECM can determine the exact
position of the camshaft at any time. Using this signal in conjunction with the signal supplied by
the crankshaft position sensor, the ECM is able to detect the firing position of the engine (i.e. the
exact position and stroke of each piston). Care must be taken to avoid fitting an incorrect
camshaft gear, as the gear used on engines equipped with GEMS EMS looks similar, but if this
gear is used in place of the correct gear, a fault will be stored, as the two gears have a different
tooth spacing pattern.
Unlike an inductive type sensor, a hall-effect sensor does not produce a sinusoidal output
voltage (sine wave).
Camshaft/Crankshaft Signal Output
Instead it produces a ‘square wave’ output. The edges are very ‘crisp’, rising very sharply and
falling very sharply, giving the ECM a defined edge on which to base its calculations. An
implausible signal will result in the following:
• The MIL lamp illuminated after ‘validating’ the fault)
• Loss of performance, due to the corrective ignition strategy being disabled. A default ignition map is used which retards the timing to a safe position
• Injector operation possibly 360° out of phase, i.e. fuel injected during compression stroke
rather than during exhaust stroke
• Quick crank/cam synchronization on start-up feature disabled
• Some Oxygen sensor diagnostics disabled
Bosch 5.2.1 Engine Management System
145
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
In addition, the ECM will store a relevant fault code and capture the input signal supplied by the
engine coolant temperature sensor, and the engine load calculation and the engine rpm at the
time of failure. TestBook will display the live readings from the camshaft sensor.
Engine coolant temperature sensor
The engine coolant temperature sensor is located near the
top of the engine, adjacent to the coolant outlet pipe. The
sensor features four electrical connections; two are used on
Discovery Series II applications and all four are used in 1999
MY Range Rover applications. The sensor conforms to the
conventional negative temperature coefficient (NTC) electrical
characteristics.
The signal supplied by the engine coolant temperature sensor
is critical to many fuel and ignition control strategies.
Therefore, the Bosch 5.2.1 system incorporates a complex
engine coolant temperature sensor default strategy, which it implements in the event of failure.
The ECM uses several alternative inputs to determine the specific default value selected in
these circumstances. The amount of time the engine has been running and the temperature of
the air entering the engine are the primary inputs used to determine the default value. The
software model of the temperature increasing will finish when it reaches a value of 150°F
(65°C). This value is then used until the engine is switched off.
The following symptoms may be noticeable in the event of an engine coolant temperature
sensor failure:
•
•
•
•
The MIL lamp illuminated (after ‘validating’ the fault)
Poor engine hot and cold start
Overheat warning lamp (incorporated within the Instrument pack) is illuminated
Excessively hot or cold needle reading on the temperature gauge
146
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM will also store details of the engine speed, engine load and air temperature in its
memory. This information is stored to aid diagnosis of the fault
Coolant Sensor Operational Values
Knock sensors
There are two knock sensors on the V-8 engine, both located
directly on the cylinder block, one on each side. The knock
sensors produce a voltage signal in proportion to the amount of
mechanical vibration generated at each ignition point. Each
sensor monitors the four cylinders in one bank.
The knock sensors incorporate a piezoceramic crystal. This
crystal produces a voltage whenever an outside force tries to
deflect it, (i.e. exerts a mechanical load onto it). When the
engine is running, the compression waves in the material of the
cylinder block, caused by the violent combustion of the fuel/air
mixture within the cylinders, deflect the crystal. As described
above, these forces acting on the crystals cause them to produce an output voltage signal.
These signals are supplied to the ECM and compared with sample ‘mapped’ signals stored
within its memory. From this, the ECM can identify when the ignition is too far advanced and
causing pre-ignition problems.
Care must be taken at all times to avoid damaging the knock sensors, but particularly during
removal and installation procedures. The recommendations regarding to torque and surface
preparation must be adhered to. The torque applied to the sensor and the quality of the surface
preparation both have an influence over the transfer of mechanical noise from the cylinder block
to the crystal.
Bosch 5.2.1 Engine Management System
147
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM uses the signals supplied by the knock sensors in conjunction with the camshaft
sensor signal, to determine the optimum ignition point for each cylinder. The ignition point is set
according to pre-programmed ignition maps stored within the ECM. In this case, the ECM is
programmed to use ignition maps for 95 RON premium specification fuel. It will also function on
91 RON regular specification fuel but without adaptations. If the only fuel available is of poor
quality, or the customer switches to a lower grade of fuel after using a high grade for a period of
time, the engine may suffer slight pre-ignition for a short period. This amount of pre-ignition will
not damage the engine. This situation will be evident while the ECM learns and then modifies its
internal mapping to compensate for the variation in fuel quality. This feature is called
‘adaptations’. The ECM has the capability of adapting its fuel and ignition control outputs in
response to several sensor inputs.
Unlike previous Land Rover engine management systems, the Bosch 5.2.1 system is capable
of advancing the ignition timing for improved power and economy, as well as retarding it.
The ECM will cancel ‘closed loop’ control of the ignition system if the signal received from either
knock sensor becomes implausible, or the signal from the camshaft sensor is corrupted at any
time. In these circumstances, the ECM will default to a safe ignition map. This measure ensures
the engine will not become damaged if low quality fuel is used. The MIL lamp will not illuminate
at this time (in any market), although the driver may notice that the engine ‘knocks’ in some
driving conditions and displays a slight drop in performance and smoothness.
When a knock sensor fault is stored, the ECM will also store details of the engine speed, engine
load and the coolant temperature.
Mass Air Flow and Intake Air Temperature sensor
The mass air flow (MAF) sensor is located in the air intake
ducting, between the air filter housing and the plenum
chamber. The MAF sensor returns a signal to the ECM to
indicate how much air is entering the engine. The amount of air
entering the engine is calculated from two functions:
1 The sensor incorporates a hot film element. This film is
heated by the circuitry in the MAF sensor. A proportion of
the air flowing into the engine flows past the film and acts
to cool it. The greater the air flow, the greater the cooling
effect. The output voltage varies in accordance with the
amount of electrical power being consumed by the mass
air flow meter to keep the film at a predetermined temperature.
2 The MAF sensor also incorporates an intake air temperature (IAT) sensor. This sensor is an
NTC type of sensor. It informs the ECM of the temperature of the air entering the engine.
The temperature of the air entering the engine will affect its density. The density of the air
entering the engine will affect its ability to support combustion. The signal supplied by the
temperature sensor is used to calculate the cooling effect on the hot film from a given mass
of air, along with several other fuelling calculations.
148
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The MAF sensor is sensitive to sudden shocks and changes in its orientation. It should,
therefore, be handled carefully. It is also important that the intake ducting between the air filter
housing and the engine plenum chamber is not altered in diameter or modified in any way. The
air mass flow meter contains electronic circuitry, so never attempt to supply it directly from the
battery. The terminals have a silver coating to provide a superior quality of connection over
many years. If, at any time, a probe is used to measure the output directly from the sensor, then
care must be taken to ensure this coating is not damaged.
If the MAF sensor signal fails then the ECM will adopt a default strategy. This strategy will cause
the ECM to assume that a certain quantity of air is entering the engine. The exact quantity will
be based upon the signals received relating to throttle position, engine speed and air
temperature. The following engine symptoms will be noticeable:
•
•
•
•
The MIL lamp will be illuminated after the fault has been ‘validated’
The engine speed might ‘dip’ before the default strategy enables continued running
The engine may be difficult to start and prone to stalling
The overall performance of the engine will be adversely affected (throttle response in particular)
• Exhaust emissions will be out of tolerance, because the air/fuel ratio value is now assumed,
not calculated; no closed loop fuelling
• Idle speed control disabled, leading to rough idle and possible engine stall
At the time of failure, the ECM will store details of the engine speed, coolant temperature and
throttle angle.
If the signal from the air temperature sensor fails, the ECM will assume a default value of 112°F
(45°C). This default value is then used within all the calculations involving intake air
temperature. The effect on the vehicle of a failed air temperature signal will not be so noticeable
to the driver, who may notice a reduction in engine performance when operating the vehicle at
high altitudes or in hot ambient temperatures. The occurrence of this fault will also disable
fuelling adaptations and the catalyst monitoring function of the ECM.
Bosch 5.2.1 Engine Management System
149
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM will store details of the engine speed, engine load and battery voltage when this fault
is first detected.
Oxygen sensors
There are four Oxygen sensors used on the V-8 Discovery Series II. Two of the sensors are
located in each downpipe.
11- “Downstream” Sensor tip
12- “Upstream” Sensor tip
One sensor is used upstream of the catalyst, i.e. between the catalyst and the engine, and one
is used immediately downstream of the catalyst. The two sensors used upstream of the catalyst
are referred to as ’pre-catalyst’ sensors (12), while the two sensors used downstream are
referred to as ’post-catalyst’ sensors (11). It should be noted that the ‘pre-catalyst’ Oxygen
sensors are not interchangeable with the ‘post’ catalyst Oxygen sensors. The pre and post
sensors can be identified by the shape of the vents on their protective metal tip shell., as shown
below.
150
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The Oxygen sensors are very sensitive devices. They must be handled carefully at all times.
Failure to handle correctly will result in a very short service life, or non-operation.
Oxygen sensors are pre-coated with an anti-seize compound prior to installation. Care should
be taken to avoid getting this compound on the sensor tip.
If the sensor needs to be removed and reinstalled, a small amount of anti-seize compound
should be applied (see workshop manual for details).
The Oxygen sensors use ‘Zirconium technology’. The sensors feature a Galvanic cell (6),
which is surrounded by a gas permeable ceramic material (9) enclosed by a protective metal
shell (10). This allows exhaust gas to come into contact with one side of the sensor. The other
side of the sensor is exposed to the atmosphere. Due to its construction, the sensor produces a
voltage. The precise value of the voltage produced is dependent upon the ratio of Oxygen in the
atmosphere compared to the Oxygen in the exhaust gas. The voltage produced for an exhaust
gas with Lambda 1 (i.e. stoichiometric air, fuel ratio of 14.7:1) is 0.45 - 0.5 volts (450 – 500 mv).
The voltage will fall in value to approximately 0.1 volts (900 mv), or Lambda 0.8, when the
Oxygen in the exhaust gas rises (lean mixture - too much air in relation to fuel). The voltage will
rise in value to approximately 0.9 volts when the Oxygen level in the exhaust gas falls to
approximately Lambda 1.2 (rich mixture - too much fuel in relation to air).
The voltage from the Oxygen sensor is communicated to the ECM via the Oxygen sensor signal
wires (1, 5). The ECM monitors the effect of altering the injector pulse widths uses the
information supplied by the Oxygen sensors. Injector pulse width is the length of time the
injector is energized, which determines how much fuel is injected. The response time is such
that under certain driving conditions, the ECM can assess individual cylinder contributions to
the total exhaust emissions. This enables the ECM to adapt the fuelling strategy on a cylinder
by cylinder basis, i.e. inject the precise amount of fuel required by each individual cylinder at
any given time.
The ECM continuously checks the signals supplied by the Oxygen sensors for plausibility. If it
detects an implausible signal, then it will store a relevant fault code. On the second concurrent
‘journey’ that a fault is recognized, the ECM will illuminate the MIL lamp and store details of
engine speed, engine load and the Oxygen sensor voltage. The ECM requires the Oxygen
sensor signals to set most of its adaptations. Failure of an Oxygen sensor will result in most of
these adaptations resetting to their default values. This, in turn, will result in the engine losing its
‘finesse’. The engine may exhibit poor idle characteristics and emit a strong smell of rotten eggs
from the exhaust (H2S).
The efficiency of the Oxygen sensors slowly deteriorates over many kilometers/miles (unless
contamination such as excessive oil or lead has occurred causing sudden damage/ failure). The
ECM is able to detect this steady deterioration using the feedback signals. When a signal from
a sensor deteriorates beyond a predetermined threshold, the ECM will illuminate the MIL lamp
and store a fault code. At the same time, the ECM will capture details of the engine speed,
engine load and battery voltage. The sensor response time will normally deteriorate over its life,
however the engine management system monitors performance, and will illuminate the MIL
when a sensor requires replacement.
Bosch 5.2.1 Engine Management System
151
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM also monitors the efficiency of the catalysts. The ECM uses the signal received from
the two post-catalyst Oxygen sensors to do this. The state of each catalyst is assessed in line
with its ability to ‘hold’ Oxygen. In a serviceable unit the ‘excess’ Oxygen in the exhaust gas is
held on the surface of the precious metal coating of the ceramic blocks within the catalyst. This
Oxygen is used to convert the harmful elements produced by incomplete combustion
(particularly during acceleration and conditions where the engine requires a rich air/fuel ratio)
into Carbon Dioxide, Nitrogen and water. By comparing the signals received from the precatalyst sensors with those received from the post-catalyst sensors, the ECM can calculate how
much Oxygen is retained by each catalyst and can, therefore, determine their condition. If the
ECM determines that one or both catalysts require replacement, then it will illuminate the MIL
(after validating the fault) and store the relevant fault code. At the same time, the ECM will
record details of the engine speed, engine load and air temperature.
Zirconium Oxygen sensors need high operating temperatures to work effectively. To ensure a
suitable operating temperature is reached as soon as possible, each sensor incorporates a
heating element inside the ceramic tip. This element heats the Oxygen sensor to a temperature
greater than 670°F (350°C). The heating rate (the speed at which the temperature rises) is
carefully controlled by the ECM to prevent thermal shock to the ceramic material. By way of a
PWM voltage supply to the heater elements, the ECM controls.
The rate at which the element temperature is increased. The sensors are heated during engine
warm-up and again after a period of engine idle.
The ECM monitors the state of the heating elements by calculating the amount of current
supplied to each sensor during operation. If the ECM identifies that the resistance of either
heating element is too high or too low, it will store a fault code, the engine speed, coolant
temperature and the battery voltage. When the fault is logged twice on consecutive ‘journeys’,
the MIL lamp will illuminate.
Immobilisation signal
The BCU sends a coded signal to the ECM before it activates the starter motor. If the ECM
accepts the immobilization signal (i.e. the code is correct), the engine will be permitted to start
and will continue to run normally. If the immobilization signal is corrupted (i.e. not sent, or
incorrect), then the ECM will allow the engine to start, but will then stop it immediately.
If the BCU is replaced during the service life of the vehicle, the immobilization code will need to
be relearned. If an attempt to start the engine is made with a new ECM installed on the vehicle
(an ECM not yet programmed with any immobilization code), the ECM will not allow the engine
to start and will store a fault code. This fault code must be cleared and the immobilization code
learned before the ECM will allow the engine to run.
The immobilization code must also be relearned in cases where an ECM from one vehicle is
used on another.
If the ECM detects an incorrect immobilization code it will store a fault code. Simultaneously, the
ECM will record the engine speed, battery voltage and the number of occurrences (the number
of times the incorrect code has been detected).
152
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Fuel level signal
This signal is supplied to the ECM by the instrument pack. It is used to alter the fault code
strategy adopted by the ECM when a misfire is detected (see misfire detection) or if the ECM
detects that the Oxygen signal is unexpectedly recording a weak air/fuel ratio. It will not stop a
fault being logged but will modify the fault code to indicate the likely cause of the misfire.
Vehicle speed sensor signal
The ECM uses this signal within its calculations for idle control. The ECM also forwards the
vehicle speed signal to the automatic gearbox TCM via the CAN bus. The vehicle speed signal
is produced by the SLABS ECU. The signal is calculated from the road speed signals of all four
wheel speed sensors.
Rough road signal
This signal is also produced by the SLABS ECU. It is derived from the variations between each
signal received from the four wheel speed sensors (see section on ABS for full description).
The ECM alters its misfire detection strategy whenever a rough road signal is received. The
ECM will not store details of a misfire fault at this time (see misfire detection strategy).
Automatic temperature control system request
A signal is supplied to the ECM whenever the ATC system requires the compressor clutch and/
or condenser fans to function. The ECM integrates the control of these components with the
engine management system. This ensures effective engine preparation for any sudden
increase in the engine load.
The ECM will turn off the ATC compressor clutch if the engine coolant temperature exceeds
255°F (124°C). The ECM will turn on the condenser fans if the engine coolant temperature
exceeds 212°F (100°C). See section on ATC for more details on the exact operation of the
compressor clutch and condenser fans.
The ECM will store engine speed, battery voltage and engine load details whenever it detects a
fault originating from the ATC circuit. It will store engine speed, intake air temperature and
details of the battery voltage if the fault relates to the compressor clutch or condenser fan
operation.
Automatic gearbox information
Information sent to and from the automatic gearbox TCM is transmitted on the CAN bus. Full
details of this information are in the section on automatic gearbox.
The ECM requires information on gear position to calculate the likely engine load during
acceleration and deceleration conditions. The ECM also disables the misfire detection function
whenever low range is selected. Information regarding range selection is supplied by the TCU.
There are several possible fault codes associated with the CAN bus and the validity of
information sent to and from the ECM from the TCU. In most cases, the ECM will store engine
speed, engine coolant temperature and details of the battery voltage at the time when the fault
is detected.
Bosch 5.2.1 Engine Management System
153
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The automatic transmission TCM is able to request the illumination of the MIL lamp if it detects
a fault within its systems that might lead to the vehicle emitting excessive levels of pollutants. It
is good practice to check both ECM and the automatic gearbox TCM for faults when the MIL
lamp is illuminated, or a MIL event is logged in the ECM.
Fuel tank pressure sensor
The fuel tank pressure sender is located in the fuel tank. This unit supplies a signal to the ECM
related to the amount of fuel vapor pressure within the fuel tank. It is used as a feedback device
within the ECM’s evaporative emission control (EVAP) leak test. This test is detailed later in the
section.
If a fault is present, the ECM will store a relevant fault code and the engine speed value, battery
voltage and details of the engine coolant temperature. If the fault happen on the next ‘journey’,
the ECM will illuminate the MIL lamp.
154
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
System Outputs
The ECM receives and processes the input information previously described and modifies the
fuelling and the ignition points for each cylinder accordingly. The ECM will also supply output
information to other vehicle system ECUs.
The ECM drives the following components:
•
•
•
•
•
Fuel injectors
Ignition coils
Idle speed actuator
Main relay and fuel pump relay
Purge valve
The ECM provides other systems with information regarding the •
•
•
•
Engine speed
Driver demand
Grant signals ATC
Grant signals Automatic Transmission
Ignition coils
The V-8 gasoline engine in Discovery Series II uses two twin-ignition coils (total of four coils).
The two coils are located behind the plenum chamber at the rear of the engine (see figure 57).
Each coil contains two primary windings and two secondary windings. There is a three-pin
connector on each coil. Pin two connects both primary windings to an ignition supply. There is
one suppression capacitor connected to each supply. This helps eliminate the effect of the
magnetic radiation created by the sudden demands for power as each coil recharges.
The system employs waste spark technology to produce a powerful and precise spark. The
cylinders are paired according to the table below.
Coil Set
Coil 1
Coil 2
Coil 3
Coil 4
Cylinders
1&6
7&4
5&8
3&2
The ECM provides a path to ground whenever a spark
is required. To ensure a sustained magnetic field
collapse, the ECM carefully controls the rate of
discharge from each coil at this time. This control also
limits the amount of heat created during this process
and reduces the total power consumed by each coil.
Any faults detected within the primary and HT circuits
will result in the ECM storing an appropriate misfire
fault, but not a fault directly related to the spark
creation and delivery.
Bosch 5.2.1 Engine Management System
155
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Fuel injectors
There are eight injectors (one per cylinder) used on the V-8
gasoline engine. The ECM controls the injectors directly,
and individually. It opens an injector by providing a path to
ground for a voltage supplied by a common fuse. The
injectors are fed fuel under pressure from a common fuel
rail. A fuel pressure relief valve, incorporated into the lift
pump assembly located inside the fuel tank, controls the
pressure in the fuel rail. In this case, the pressure is
controlled to a fixed value of 51 psi (3.5 Bar). As indicated,
the fuel pressure is fixed and the relief valve provides no
compensation for increases or decreases in manifold
vacuum. The ECM alters injector duration to accommodate
such changes.
Connecting an appropriate gauge to the Schrader valve on the fuel rail provides a method of
checking the fuel pressure. The valve is located to the rear of injector no. 7. Considerable care
must be taken whenever making this connection.
Each injector is sealed with two ‘O’ rings. These ‘O’ rings should be renewed whenever an
injector is reinstalled on an engine. A small amount of engine oil can be applied to the ‘O’ rings
to aid installation. No other form of lubrication should be used.
Measuring the electrical resistance of the injectors internal coil enables an assessment to be
made of the serviceability of an injector. An injector in a serviceable condition should possess a
resistance of 14.5 ohms at 68°F (20°C) with a tolerance of ± 0.7 ohms.
The ECM can detect electrical inconsistencies within each injector. It can also detect, via
feedback from the Oxygen sensors, mechanical faults such as blockage or leakage. The ECM
will store a relevant fault code in these circumstances. The ECM will also store the engine
speed, engine load and details of one of the following: battery voltage, engine coolant
temperature or intake air temperature. The precise details stored depend on the exact nature of
the fault detected.
TestBook will also display data regarding injector operation via its live readings. Care must be
taken when analyzing this data, as the precise timings will vary considerably. Individual timings
will be affected by any current engine load.
156
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Idle speed actuator
The idle speed control actuator is located behind the throttle body on the intake manifold. It is
connected to the intake manifold by two hoses. One hose connects upstream and the other
connects downstream of the throttle valve. Therefore, the idle speed actuator effect provides an
air bypass for the throttle valve.
The ECM controls the engine idle speed via the idle speed actuator. It does this by allowing a
measured quantity of air into the engine when the throttle valve is closed. The idle speed
actuator comprises a rotary valve and two electrical coil windings. The ECM alters the position
of the idle speed actuator and, therefore, the amount of air bypassing the closed throttle valve
by providing a PWM voltage to the two opposing coils inside the actuator. These coils control
the position of the rotary valve by producing opposing magnetic fields. When the ECM identifies
a need for a higher idle speed it enables a greater quantity of air to bypass the throttle valve. It
does this by altering the PWM voltage supplied to both coils. This provides an imbalance in
magnetic fields inside the actuator and, in turn, alters the amount of air bypassing the throttle
valve.
The ECM controls the position of the rotary valve within the idle speed actuator to maintain a
stable idle speed in all conditions. It will alter the position to obtain a pre-set target speed. The
precise pre-set idle speed will vary according to the operating conditions of the engine and the
transmission gear that is selected. These pre-set speeds are detailed in the table below.
Condition
Air conditioning
status
Target idle speed (rpm)
high range
Target idle speed (rpm)
low range
First 20 seconds after a cold start
N/A
1200
1200
Low battery voltage detected
N/A
850
850
Drive selected
On
740
580
Park/ neutral selected
On
740
580
Drive selected
Off
660
580
Park/ neutral selected
Off
660
580
Bosch 5.2.1 Engine Management System
157
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
For 20 seconds immediately following cold start, the idle speed will be raised to 1200 rpm. At
the same time the ECM will retard the ignition timing. These actions ensure the engine and the
catalysts reach their operating temperatures as quickly as possible.
The ECM can identify faults with the circuitry used to control the position of the idle speed
actuator. In circumstances where it detects a fault with one coil it will de-energise the other coil.
This action prevents the idle speed control valve being driven to a fully open or fully closed
position. The idle speed control actuator contains two permanent magnets inside the body.
These magnets will determine the position of the valve at this time. In this position the engine
will idle at approximately 1200 rpm. This state should not be confused with the target idle speed
initiated by the ECM for the first 20 seconds immediately following cold engine start.
The ECM will store fault codes relating to the electrical properties of the idle speed actuator and
to associated failures, such as poor engine response to movement of the rotary valve. The
associated data stored will depend upon which fault is detected, such as battery voltage, engine
coolant temperature and throttle angle for faults related to the circuitry; or engine speed, engine
coolant temperature and intake air temperature for ‘poor response’ fault codes.
If ECM control of the idle speed actuator is suspended, (i.e. fault stored), then the driver may
notice the following symptoms relating to engine performance:
•
•
•
•
The engine will exhibit poor idle stability
The engine will exhibit a high idle speed
The engine will be prone to stalling
The engine will be difficult to start
Main relay and fuel pump relay
The ECM controls the main relay and the fuel pump relay. They are both located in the underhood fuse box.
The ECM energizes the fuel pump relay when the ignition is first turned to position II. It also
energises it during engine cranking and when the engine is running.
158
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM controls its own power supply, via the main relay. When the ignition is turned to
position II, the ECM provides a ground to the relay coil winding. This, in turn, connects the main
power feed to the ECM. The ECM controls the main relay and therefore its own power, so that
when the ignition is turned off it can follow the previously described power-down sequence,
during which it records values from various sensors and writes adaptations into its memory, etc.
The last action the ECM carries out before completing its power-down sequence is to turn off
the main relay. This will occur approximately 15 seconds after the ignition has been switched
off, as long as the coolant temperature is not rising.
The ECM monitors the state of the wiring to the coil winding within the fuel pump relay. The
ECM will store relevant fault codes if the ECM detects a problem. The ECM is not able to
assess the state of the fuel pump circuit because it is isolated by the function of the relay.
However, if the fuel pump circuit fails, or the pump fails to deliver sufficient fuel (while the fuel
level is above its minimum), the ECM will store adaptive faults as it tries to increase the air/fuel
ratio by increasing the duration (pulse width) of the injectors.
Failure of the main relay will result in engine non-start. The engine will cease to operate if the
main relay fails while the engine is running.
Failure of the fuel pump relay will result in engine non-start. If the fuel pump fails while the
engine is running, the symptoms will be engine hesitation and engine misfire. These symptoms
will worsen progressively until the engine stops. The ECM will store several fault codes under
this condition.
Purge valve
The purge valve is located on the right hand side of the engine (when viewed from the front of
the vehicle) forms part of the evaporative emission control system (EVAP) and is situated in the
line between the charcoal canister and the manifold. The purge valve controls the amount of air/
fuel vapor drawn from the canister into the engine. The other components incorporated into the
EVAP system are:
• The charcoal canister, which is located on the right hand inner chassis rail by the hand
Bosch 5.2.1 Engine Management System
159
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
brake drum
• The fuel tank pressure sensor, located in the fuel sender unit
• The intake manifold
The ECM controls the amount of vapor drawn from the charcoal canister by controlling the
length of time the purge valve is open. It controls the length of time it is open by supplying the
purge valve with a PWM voltage. Control is used to maintain the required level of emissions, as
a hydrocarbon vapor level of 1% can affect the air/fuel ratio by as much as 20%.
The ECM can diagnose faults with the purge valve and the rest of the EVAP system. The ECM
will store the relative fault codes, along with details of the engine speed, battery voltage and air
temperature. The driver may notice the following effects in circumstances where the EVAP
system has failed:
• The engine may stall periodically when returning to idle
• The engine may suffer from poor idle quality
OTHER ECM OUTPUTS
Engine speed
The engine speed signal is supplied from the ECM to the automatic gearbox TCM via the CAN
bus. All other systems requiring the engine speed input receive a frequency dependent square
wave supplied by the ECM.
Driver demand
The ECM receives and processes the signal supplied by the throttle position sensor. It then
digitises this information, which enables it to supply a driver demand signal, via the CAN bus, to
the automatic gearbox TCM or, by a PWM signal, to any other system requiring this information.
ATC grant signal
The ECM supplies a signal to the ATC Compressor relay to activate the compressor.
Torque reduction grant signal
The ECM also informs the automatic gearbox TCM if its torque reduction request has been
granted.
160
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
ECM Adaptations
The ECM, as previously mentioned, has the ability to adapt the values it uses to control certain
outputs. This capability ensures the EMS can meet emissions legislation and improve the
refinement of the engine throughout its operating range.
The components which have adaptations associated with them are:
•
•
•
•
•
The idle speed control (ISC) valve
The throttle position sensor (TPS)
The Heated Oxygen sensors (HO2S)
The airflow sensor (MAF)
The crankshaft sensor (CKP)
Idle speed control valve
Over a period of time, the ECM adapts the position it sets the idle speed control valve. The
adaptations are made relative to engine coolant temperature and engine load. When a new idle
speed control valve or a replacement ECM is used, this adaptation should be reset.
Subsequently, the ECM will make further adaptations to suit the particular characteristics of the
new or replacement components. Failure to reset the original adaptation may result in a
prolonged period of poor idling. During this time the ECM slowly adapts the original, ‘incorrect’
value stored in its memory.
TestBook will display the adaptation currently being applied against the model programmed into
its memory. This can be used to indicate the possible cause of problems relating to the amount
of air entering the engine, such as air blockages or air leaks within the induction system.
Throttle position sensor
The ECM ‘learns’ the closed position of the throttle position sensor. The closed voltage value
supplied by the sensor is stored by the ECM and can be read using TestBook (see TPS sensor
for information regarding the likely readings and signal tolerance band). If the sensor is
replaced, the new closed throttle position will be learned by the ECM during the IMF cycle for
the TPS.
The signal from the TPS sensor is used in conjunction with the air mass flow meter to calculate
the altitude adaptations. This adaptation affects the amount of fuel entering the engine and the
ignition timing. Details of the value of this adaptation are supplied to the automatic gearbox
TCM. Using this information, it will adapt its gear change control maps. The altitude adaptation
is continuously changing and indicates current driving conditions. Details of the altitude
adaptation are stored within the ECM’s memory when the ignition is switched off. This enables
the ECM to provide correct fuelling on the next engine start.
Oxygen sensors & air flow meter
There are several adaptive maps associated with the fuelling strategy. Within the fuelling
strategy the ECM calculates short-term adaptations and long term adaptations. The ECM will
monitor the deterioration of the Oxygen sensors over a period of time. It will also monitor the
current correction associated with the sensors.
Bosch 5.2.1 Engine Management System
161
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
The ECM will store a fault code in circumstances where an adaptation is forced to exceed its
operating parameters. At the same time, the ECM will record the engine speed, engine load and
intake air temperature.
Crankshaft position sensor
The characteristics of the signal supplied by the crankshaft position sensor are learned by the
ECM. This enables the ECM to set an adaptation and support the engine misfire detection
function. Due to the small variation between different flywheels and different crankshaft
sensors, the adaptation must be reset if either component is renewed, or removed and
replaced. It is also necessary to reset the flywheel adaptation if the ECM is renewed or
replaced.
The ECM supports four flywheel adaptations for the crankshaft position sensor. Each adaptation
relates to a specific engine speed range. The engine speed ranges are detailed in the table
below.
Engine speed range
Adaptation
1800 – 3000
1.00
3001 – 3800
2.00
3801 – 4600
3.00
4601 - 5400
4.00
To set the flywheel adaptations, follow the procedure detailed below. This procedure should be
carried out in an appropriate area off the public highway. TestBook must be connected
throughout this procedure. The adaptive speed settings must be read from TestBook while the
vehicle is moving at speed.
1 Use TestBook to clear any adaptations currently set.
2 With the engine warm >187°F (86°C) select 2nd gear high range
3 Accelerate the vehicle until the engine speed reaches the rpm limiter
4 Release the throttle and allow the vehicle to decelerate until the engine idle speed is
reached
5 Check that one of the speed range adaptations has been set (read this from TestBook)
6 Repeat the above procedure until all four adaptations are set
When all four adaptations have been set, check that the ECM has not recorded any misfire
detection faults. If it has, then clear the memory of the fault codes.
It may not be possible to reset adaptation number 4 if the ECM has already been programmed
with a value. Due to the nature of the procedure and the self learn capacity of the ECM, if
adaptation number 4 does not reset, it is permissible to leave this adaptation and let the ECM
learn it.
162
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Misfire detection
Legislation requires that the ECM must be able to detect the presence of an engine misfire. It
must be able to detect misfires at two separate levels. The first level is a misfire that could lead
to the vehicle emissions exceeding 1.5 times the allowable levels for this engine. The second
level is a misfire that may cause catalyst damage.
The ECM monitors the number of misfire occurrences within two engine speed ranges. If the
ECM detects more than a predetermined number of misfire occurrences within either of these
two ranges, over two consecutive ‘journeys’, the ECM will illuminate the MIL. The ECM will also
record details of the engine speed, engine load and engine coolant temperature. In addition, the
ECM monitors the number of misfire occurrences that happen in a ‘window’ of 200 engine
revolutions. The misfire occurrences are assigned a ‘weighting’ of the likely impact to the
catalysts. If the number of misfires exceeds a certain value, the ECM stores catalyst-damaging
fault codes, along with the engine rpm, engine load and engine coolant temperature. It will also
flash the MIL lamp until the misfires no longer exceed the predetermined number. After the
flashing stops, the ECM will continue to illuminate the MIL lamp until the fault is rectified.
The signal from the crankshaft position sensor indicates how fast the poles on the flywheel are
passing the sensor tip. A sine wave is generated each time a pole passes the sensor tip. The
ECM can detect variations in flywheel speed by monitoring the sine wave signal supplied by the
crankshaft position sensor.
By assessing this signal, the ECM can detect the presence of an engine misfire. At this time, the
ECM will assess the amount of ‘variation’ in the signal received from the crankshaft position
sensor and assigns a ‘roughness’ value to it. This roughness value can be viewed within the
real time monitoring feature, using TestBook. The ECM will evaluate the signal against a
number of factors and will decide whether to count the occurrence or ignore it. The ECM can
assign a roughness and misfire signal for each cylinder, (i.e. identify which cylinder is misfiring).
Bosch 5.2.1 Engine Management System
163
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
TestBook Diagnostics
The ECM will, as explained earlier, store fault codes and environmental data. The ECM also
records additional data in connection with each fault. The additional data recorded is as follows:
1 The number of occurrences
2 If the fault is currently present
3 If the fault is historic, the number of ‘journeys’ that have elapsed since the fault last
occurred.
4 The ‘current time’ stored when the fault occurred. (The time is incremented in hours, hour 0
being the first time the ECM is powered-up, hour 1 being 60 minutes of ignition ‘on’ time,
etc.)
This information is displayed for each fault, along with an explanation of the fault code and the
stored environmental data. All the above information is stored and displayed to assist with
effective fault diagnosis and repair.
TestBook can also read real time data from each sensor, the adaptive values currently being
employed and the current engine fuelling, ignition and idle settings. The live readings are
displayed first as a page of readings. To gain more detail press and highlight the reading for
which you require more information.
164
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Connector Pinouts
Bosch 5.2.1
Connector 1
C0634 (9-way, Black)
PIN
Wire
Color
Description
Voltage Reading
1
W
Ignition sense (position II)
12 V
2
-
3
-
4
B
Chassis Earth
0V
5
B
Fuel Injectors Earth
0V
6
B
Power stage Earth
0V
7
PY
Permanent Battery supply
12 V
8
NO
Switched Relay positive
0-12V
9
-
Bosch 5.2.1 Engine Management System
165
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Connector 2
C0635 (24-way, Black)
PIN
Wire
Color
Description
PIN
Wire
Color
Description
1
WU
HO2S Heater Bank B - 12-0V
downstream
13
WO
HO2S Heater Bank B -up- 12-0V
stream
2
-
14
G
HO2S signal Bank B-down- 0-1V
stream
3
-
15
O
HO2S signal Bank A -up- 0-1V
stream
4
-
16
U
HO2S signal Bank B -up- 0-1V
stream
17
Y
HO2S signal Bank A - 0-1V
downstream
18
UP
Fuel pump relay [PWM]
HO2S Heater Bank A -up- 12-0V
stream
5
Signal
Range
Thermostat
Monitoring 0V
Thermistor Ground
6
-
7
WU
HO2S Heater Bank A- 12-0V
downstream
19
WO
8
RB
HO2S Earth
downstream
B- 0V
20
-
9
RB
HO2S Earth Bank A -up- 0V
stream
21
10
RB
HO2S Earth Bank B -up- 0V
stream
22
-
11
RB
HO2S Earth
downstream
23
UR
12
-
166
Bank
Bank
A- 0V
24
Signal
Range
12-0V
Thermostat
Monitoring 0-5V
Thermistor Signal
Main Relay Output [Earth]
0V
DMTL Pump Motor
12-0V
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Connector 3
C0636 (52-way, Black)
PIN
Wire
Color
Description
Signal
Range
PIN
Wire
Color
Description
Signal
Range
1
YW
Injector # 2 driver, sw. -Earth
0V
27
YB
Injector # 3 driver, sw. - Earth
0V
2
YG
Injector # 5 driver, sw. -Earth
0V
28
YK
Injector #8 driver, sw. -Earth
0V
3
NR
Purge valve driver [PWM]
12-0V
29
SP
Hill descent control [PWM]
0-12V
SAI Valve solenoid
12-0V
30
SY
Can. vent solenoid, sw. - Earth
0V
31
GW
Air cond. condenser fan drive
0V
Crankshaft sensor signal
0-300V
4
5
-
6
RB
Fuel Tank pressure sensor Earth
0V
32
BY
7
R
Air flow meter 5V supply
5V
33
-
8
-
34
SLG
Air temperature signal
0-5V
9
RB
Air flow meter earth
0V
35
W
Knock sensor Bank B Earth
0V
10
R
Throttle Pot 5V Supply
5V
36
KB
Knock sensor Bank B Input
Analog
11
-
37
-
12
-
38
-
13
-
39
-
14
YR
Injector #7 driver / sw - Earth
40
YN
Injector # 4 driver, sw. -Earth
0V
15
YS
Injector #6 driver / sw - Earth
41
YU
Injector # 1 driver, sw. -Earth
0V
16
0V
SAI Pump Relay
12-0V
42
US
Idle speed actuator open
12-0V
17
B
Cam Sensor earth
0V
43
RG
Idle speed actuator close
12-0V
18
-
Low Range Switch(Manual only)
12-0V
44
GU
Coolant Temperature output
0-12V
19
-
45
SCR
CKP shield Ground
0V
20
SU
Camshaft sensor Input signal
0-12V
46
KB
CKP Ground Ref.
0V
21
RB
Coolant sensor Earth
0V
47
-
22
G
Coolant temperature signal Input
0-5V
48
B
Knock sensor Bank B Earth
0V
23
UG
Air flow meter signal Input
0-5V
49
KW
Knock sensor Bank A Input
Analog
24
YLG
TPS signal
0-5V
50
-
25
RB
TPS Ground
0V
51
-
26
-
52
-
Bosch 5.2.1 Engine Management System
167
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Connector 4
C0637 (40-way, Black)
PIN
Wire
Color
1
PIN
Wire
Color
-
21
-
2
-
22
KG
3
-
23
-
4
-
24
-
5
-
25
-
6
RK
26
-
7
-
27
-
8
GS
Low Fuel Signal
28
-
9
R
Fuel Tank pressure sensor 5V
Vref
29
BS
10
-
30
-
11
-
31
-
32
12
Description
T-box Low Range Switch
Analogue Fuel Level
Signal
Range
0V=
Low box
Active=
High
0-5V
Description
Signal
Range
Road speed Signal [PWM]
0-12V
A/C. compressor “Grant”
switch to earth
0V
K
Diagnostic K-Line Serial com.
0-12V
33
LGS
Immobiliser serial W-link
0-12V
34
RG
Rough Road signal [PWM]
0-12V
35
-
13
-
14
GK
15
-
16
YS
A/Conditioning request Input
Active=
Low
36
W
CAN bus ‘high’ line
Bi-directional comms.
5-2.5V
17
WS
Engine speed output
0-5V
37
Y
CAN bus ‘low’ line
Bi-directional comms.
0-2.5V
18
-
38
PW
A/C stand-by Signal
Active=
Low
19
-
39
-
20
RS
40
-
168
Fuel Tank pressure signal
MIL ‘on’ Output;
“ON” = earth
0-5V
0V
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Connector 5
C0638 (9-way, Black)
PIN
Wire
Color
Description
Voltage Reading
1
-
2
U
Ignition driver, Cyl # 2 , 3 Output
Switch to Earth
3
-
4
-
5
B
Ignition Coil Ground
0V
6
KB
Ignition driver, Cyl # 1 , 6 Output
Switch to Earth
7
WU
Ignition driver, Cyl # 4 , 7 Output
Switch to Earth
8
R
Ignition driver, Cyl # 5 , 8 Output
Switch to Earth
9
-
Bosch 5.2.1 Engine Management System
169
BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
170
BOSCH ME 7.2 ENGINE MANAGEMENT
BOSCH ME 7.2 ENGINE MANAGEMENT
Introduction
The Bosch ME 7.2 engine management system (EMS) is similar to the Bosch 5.2.1 system
used in previous Land Rover V8 engines. The main difference between the two systems is the
“drive by wire” capabilities of the ME 7.2 EMS.
Another main difference between the 5.2.1 system and the ME 7.2 system is that ME 7.2 uses
the Keyword protocol 2000* (KWP2000*) which is an ISO 91414 K line compatible version of
the Key Word 2000 protocol.
Engine Management Component Location, Sheet 1 of 2
1
ECM
5
Mass Air Flow/Inlet Air Temperature (MAF/IAT) sensor
2
Variable Camshaft Control (VCC) solenoid
6
Crankshaft Position (CKP) sensor
3
Knock sensor (x4)
7
Electric throttle
4
Heated thermostat
8
Main relay
Bosch ME 7.2 ENGINE MANAGEMENT
171
BOSCH ME 7.2 ENGINE MANAGEMENT
Engine Management Component Location, Sheet 2 of 2
4
3
2
1
5
14
13
6
12
11
7
8
9
7
10
M18 0797
172
1
Radiator outlet temperature sensor
8
Instrument pack
2
Engine Coolant Temperature (ECT)
sensor
9
Diagnostic socket
3
Ignition coil
10
Accelerator Pedal Position (APP)
sensor
4
Injector
11
Camshaft Position (CMP) sensor
5
Spark plug
12
E-box temperature sensor
6
Purge valve
13
EAT ECU
7
Oxygen sensors
14
E-box
BOSCH ME 7.2 ENGINE MANAGEMENT
Engine Management Control Diagram, Sheet 1 of 2
2
1
5
4
3
22
6
21
7
20
19
8
18
9
17
16
15
14
10
12
11
13
D
A
J
M18 0805A
A
Hardwired connections
7
ABS modulator/ECU
16
Vacuum vent valve
D
CAN bus
8
Diagnostic socket
17
SAI pump relay
J
Diagnostic ISO 9141 K line bus
EAT ECU
18
ECM
1
APP sensor
10
Electric cooling fan
19
LH bank VCC solenoid
2
Instrument pack
11
Starter motor
20
RH bank VCC solenoid
3
Radiator outlet temperature sensor
12
Immobilisation ECU
21
Brake light switch
4
Ignition warning lamp
13
HO2S (x 4)
22
Cruise control switches
5
Steering angle sensor
14
Comfort start relay
6
Alternator
15
SAI pump
Introduction
9
173
BOSCH ME 7.2 ENGINE MANAGEMENT
Engine Management Control Diagram, Sheet 2 of 2
3
2
1
4
20
5
19
6
7
17
18
8
9
16
10
15
14
12
11
13
A
M18 0825
A
A = Hardwired connection
7
Crankshaft Position (CKP) sensor
14
Ignition coil
1
MAF/IAT sensor
8
Fuse 25
15
Tank leakage detection module
2
Camshaft sensor
Main relay
16
Electric throttle
3
Immobilisation ECU
10
Ignition switch
17
Radiator outlet temperature sensor
4
Injector
11
Fuel pump
18
ECM
5
Auxiliary cooling fan relay
12
Ignition coil relay
19
Electrical heated thermostat
6
Purge valve
13
Fuel pump relay
20
Knock sensors
174
9
BOSCH ME 7.2 ENGINE MANAGEMENT
Key Functions
The key functions of the Bosch ME 7.2 engine management system are:
•
•
•
•
•
•
•
•
•
•
•
To control the amount of fuel supplied to each cylinder
To calculate and control the exact point of fuel injection
To calculate and control the exact point of ignition in each cylinder
To optimize adjustment of the injection timing and ignition timing to deliver the maximum
engine performance throughout all engine speed and load conditions
To calculate and maintain the desired air/fuel ratio, to ensure the 3 way catalysts operate at
their maximum efficiency
To maintain full idle speed control of the engine
To ensure the vehicle adheres to the emission standards (set at the time of homologation)
To ensure the vehicle meets with the fault handling requirements, as detailed in the European On-Board Diagnostic (EOBD) III legislation
To provide an interface with other electrical systems on the vehicle
To facilitate the drive by wire functions
To control the Variable Camshaft Control (VCC).
To deliver these key functions, the Bosch ME 7.2 Engine Control Module (ECM) relies upon a
number of inputs and controls a number of outputs. As with all electronic control units, the ECM
needs information regarding the current operating conditions of the engine and other related
systems before it can make calculations, which determine the appropriate outputs. A Controller
Area Network (CAN) bus is used to exchange information between the ECM and the Electronic
Automatic Transmission (EAT) ECU
ECM
The ECM is located in the Environmental (E) box, in the front right corner of the engine
compartment. The E-box provides a protective environment for the ECM and is cooled by an
electric fan. The main relay for the ECM is also located in the E-box.
Key Functions
175
BOSCH ME 7.2 ENGINE MANAGEMENT
E-Box
1
Fuse block
4
ECM
2
Cooling fan
5
E Box temperature sensor
3
Main relay
6
EAT ECU
A separate temperature sensor is used to monitor E-box temperature and provides a path to
earth to control the electric fan. The sensor turns the fan on when the E-box temperature
reaches 35°C (95 °F) and turns the fan off when the temperature drops below 35°C (95 °F). The
E-box fan draws air in from the passenger compartment, into the E-box and vents back into the
passenger compartment. The fan is also driven for a short period on engine crank,
independently of temperature. This is done to ensure the correct function of the fan.
176
BOSCH ME 7.2 ENGINE MANAGEMENT
The ECM is programmed during manufacture by writing the program and the engine tune into a
Flash Electronic Erasable Programmable Read Only Memory (EEPROM). The EEPROM can
be reprogrammed in service using TestBook/T4. In certain circumstances, it is possible to alter
the tune or functionality of the ECM using this process.
Advanced fault monitoring is incorporated into the ECM. It can detect the type and severity of
faults, store relevant engine operating conditions (environmental and freeze frame data) and
time that a fault occurs, suspend the operation of some functions and replace the inputs from
faulty sensors with default values. Environmental data is stored for each fault detected, and
consists of the inputs from three engine sensors, with the inputs stored depending on the fault.
The ECM also records additional data in connection with each fault, as follows:
• The number of occurrences
• If the fault is currently present
• If the fault is historic, the number of drive cycles that have elapsed since the fault last
occurred
• The time the fault occurred. Time is incremented in hours, hour 0 being the first time the
ECM is powered-up, hour 1 being 60 minutes of ignition 'on' time, etc.
OBD freeze frame data is only stored for emissions related faults. Only one set of freeze frame
data can be stored at any one time. Faults are prioritized according to their likely impact on
exhaust gas emissions. If more than one emissions related fault occurs, freeze frame data is
stored for the fault with the highest priority. Freeze frame data consists of the following:
•
•
•
•
•
•
•
Engine speed
Engine load
Short term fuelling trim of LH and RH cylinder banks
Long term fuelling trim of LH and RH cylinder banks
Fuelling status of LH and RH cylinder banks
Engine coolant temperature
Road speed.
Fault information is stored in a volatile Random Access Memory (RAM) in the ECM, so will be
deleted if a power failure or battery disconnection occurs.
Five electrical connectors provide the interface between the ECM and the engine/vehicle wiring.
The five connectors interlock with each other when installed in the ECM. Adjacent connectors
should be disconnected in turn. The installation sequence is the reverse of removal. Each
connector groups associated pins together.
ECM
177
BOSCH ME 7.2 ENGINE MANAGEMENT
System Inputs
The ECM optimizes engine performance by interpreting signals from numerous vehicle sensors
and other inputs. Some of these signals are produced by the actions of the driver, some are
supplied by sensors located on and around the engine and some are supplied by other vehicle
systems. The inputs are as follows:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ignition switch
APP sensor
Throttle position feedback
Crankshaft Position (CKP) sensor
Cruise control signal (from steering wheel switch pack)
Brake light switch
Camshaft Position (CMP) sensors
Engine Coolant Temperature (ECT) sensor
Knock sensors
Mass Air Flow/Intake Air Temperature (MAF/IAT) sensor
Heated Oxygen Sensors (HO2S)
Immobilisation signal (from immobilisation ECU)
Fuel level signal (via CAN)
Vehicle speed signal (from ABS ECU)
Radiator outlet temperature
Internal ambient barometric pressure sensor (altitude sensor)
Electronic Automatic Transmission (EAT) information.
Electric Throttle System
The EMS incorporates an electric throttle control system. This system consists of three main
components:
• Electronic throttle control valve
• APP sensor
• ECM.
When the accelerator pedal is depressed the APP sensor provides a change in the monitored
signals. The ECM compares this against an electronic “map” and moves the electronic throttle
valve via a pulse width modulated control signal which is in proportion to the APP angle signal.
The system is required to:
• Regulate the calculated intake air load based on the accelerator pedal sensor input signals
and programmed mapping
• Monitor the drivers input request for cruise control operation
• Automatically position the electronic throttle for accurate cruise control
• Perform all dynamic stability control throttle control interventions
• Monitor and carry out maximum engine and road speed cut out.
178
BOSCH ME 7.2 ENGINE MANAGEMENT
Accelerator Pedal Position (APP) Sensor
1
Detente mechanism
5
Cables
2
Sensor spigot
6
Bush
3
Pedal
7
Drum
4
Springs
8
APP sensor
The APP sensor is located in a plastic housing which is integral with the throttle pedal. The
housing is injection moulded and provides location for the APP sensor. The sensor is mounted
externally on the housing and is secured with two Torx screws. The external body of the sensor
has a six pin connector which accepts a connector on the vehicle wiring harness.
The sensor has a spigot which protrudes into the housing and provides the pivot point for the
pedal mechanism. The spigot has a slot which allows for a pin, which is attached to the sensor
potentiometers, to rotate through approximately 90°, which relates to pedal movement. The
pedal is connected via a link to a drum, which engages with the sensor pin, changing the linear
movement of the pedal into rotary movement of the drum. The drum has two steel cables
attached to it. The cables are secured to two tension springs which are secured in the opposite
end of the housing. The springs provide 'feel' on the pedal movement and require an effort from
the driver similar to that of a cable controlled throttle. A detente mechanism is located at the
forward end of the housing and is operated by a ball located on the drum. At near maximum
throttle pedal movement, the ball contacts the detente mechanism. A spring in the mechanism
is compressed and gives the driver the feeling of depressing a 'kickdown' switch when full pedal
travel is achieved.
Electric Throttle System
179
BOSCH ME 7.2 ENGINE MANAGEMENT
APP Sensor Output Graph
A
Voltage
B
APP sensor angle
C
Kickdown angle
The APP sensor has two potentiometer tracks which each receive a 5V input voltage from the
ECM. Track 1 provides an output of 0.5V with the pedal at rest and 2.0V at 100% full throttle.
Track 2 provides an output of 0.5V with the pedal at rest and 4.5V at 100% full throttle. The
signals from the two tracks are used by the ECM to determine fuelling for engine operation and
also by the ECM and the EAT ECU to initiate a kickdown request for the automatic
transmission.
The ECM monitors the outputs from each of the potentiometer tracks and can determine the
position, rate of change and direction of movement of the throttle pedal. The 'closed throttle'
position signal is used by the ECM to initiate idle speed control and also overrun fuel cut-off.
180
BOSCH ME 7.2 ENGINE MANAGEMENT
Electric Throttle
Electric Throttle Control Valve
The Electric Throttle control valve is controlled by the APP sensor via the ECM. The throttle
valve plate is positioned by gear reduction DC motor drive. The DC motor is controlled by a
proportionally switched high/low PWM signals at a basic frequency of 2000 Hz. Engine idle
speed control is a function of the Electric Throttle control valve, therefore a separate idle control
valve is not required.
The electric throttle control valve throttle plate position is monitored by two integrated
potentiometers. The potentiometers provide DC voltage feedback signals to the ECM for throttle
and idle control functions.
Potentiometer one is used as a the primary signal, potentiometer two is used as a plausibility
check through the total range of throttle plate movement.
If the ECM detects a plausibility error between Pot 1 and Pot 2 it will calculate the inducted air
mass from the air mass (from the air mass sensor) and only utilize the potentiometer signal
which closely matches the detected intake air mass. It does this to provide a fail-safe operation
by using a 'virtual' potentiometer as a comparative source.
If the ECM cannot calculate a plausible value from the monitored potentiometers (1 and 2) the
throttle motor is switched off and the fuel injection cut out is activated.
The electric throttle control valve is continuously monitored during operation. It is also briefly
activated when the ignition switch is initially turned to position II. This is done to check the
valves mechanical integrity by monitoring the motor control amperage and the reaction speed of
the feedback potentiometers.
Should the electronic throttle need replacing the adaption values of the previous unit will need
to be cleared from the ECM. This is achieved by the following process:
• Using TestBook/T4 clear the adaption values
• Switch the ignition “OFF” for 10 seconds
• Switch the ignition “ON”, for approximately 30 seconds the electric throttle control valve is
briefly activated allowing the ECM to learn the new component
Electric Throttle System
181
BOSCH ME 7.2 ENGINE MANAGEMENT
This procedure is also necessary after the ECM has been replaced. However the adaption
values do not require clearing since they have not yet been established.
Crankshaft Position (CKP) Sensor
The CKP sensor is located in the transmission bell housing adjacent to the edge of the flexplate
flywheel. The sensor reacts to a toothed reluctor ring incorporated into the flexplate to ascertain
engine speed and position information. The sensor is located on a split spacer and is secured in
position by two tube spacers and nuts. The split spacer is 18 mm thick on vehicles fitted with
automatic transmission. The thickness of the split spacer determines how far the sensor
protrudes through the cylinder block and, therefore, sets the position of the sensor in relation to
the reluctor ring. The sensor and the spacer are covered by a protective heat shield. The sensor
has three wires attached to it; two signal wires and a screen. The sensor earth screen is
connected to chassis earth through the ECM.
CKP Sensor
The CKP sensor is an inductive type sensor which produces a sinusoidal output voltage signal.
This voltage is induced by the proximity of the moving reluctor ring, which excites the magnetic
flux around the tip of the sensor when each tooth passes. This output voltage will increase in
magnitude and frequency as the engine speed rises and the speed at which the teeth on the
reluctor ring pass the sensor increases. The signal voltage will peak at approximately 6.5 volts if
connected to the ECM (further increases in engine speed will not result in greater magnitude).
The ECM neither specifically monitors nor reacts to the output voltage (unless it is very small or
very large), instead it measures the time intervals between each pulse (i.e. signal frequency).
The signal is determined by the number of teeth passing the sensor, and the speed at which
they pass. The reluctor ring has 58 teeth spaced at 6° intervals, with two teeth missing to give
the ECM a synchronisation point.
182
BOSCH ME 7.2 ENGINE MANAGEMENT
The signal produced by the CKP sensor is critical to engine running. There is no back-up
strategy for this sensor and failure of the signal will result in the engine stalling and/or failing to
start. If the sensor fails when the engine is running, then the engine will stall, a fault code will be
stored and details captured of the battery voltage, engine coolant temperature and intake air
temperature at the time of the failure. If the signal fails when the engine is cranking, then the
engine will not start and no fault will be stored, as the ECM will not detect that an attempt had
been made to start the engine. In both cases the tachometer will also cease to function
immediately and the MIL lamp will be permanently illuminated.
During the power-down procedure, which occurs when the ignition is switched off, the ECM
stores details of the position of the CKP and CMP sensors. This enables the ECM to operate
the injectors in the correct sequence immediately the engine cranks, to produce a quick engine
start, which serves to reduce emissions when the engine is cold.
Camshaft Position (CMP) Sensor
There are two CMP sensors which are located on the upper timing case covers. The CMP
sensors monitor the position of the camshafts to establish ignition timing order, fuel injection
triggering and for accurate Variable Camshaft Control (VCC) camshaft advance-retard timing
feedback. The CMP sensor is a Hall-effect sensor which switches a battery fed supply on and
off. The supply is switched when the teeth machined onto the camshaft gear pass by the tip of
the sensor. The four teeth are of differing shapes, so the ECM can determine the exact position
of the camshaft at any time.
CMP Sensor
Unlike an inductive type sensor, a Hall-effect sensor does not produce a sinusoidal output
voltage (sine wave). Instead it produces a square wave output. The wave edges are very sharp,
giving the ECM a defined edge on which to base its calculations.
An implausible signal from the CMP sensor will result in the following:
• The MIL lamp illuminated after debouncing the fault
• Loss of performance, due to the corrective ignition strategy being disabled. A default ignition map is used which retards the timing to a safe position
• Injector operation possibly 360° out of phase, i.e. fuel injected during exhaust stroke rather
Electric Throttle System
183
BOSCH ME 7.2 ENGINE MANAGEMENT
than during compression stroke
• Quick crank/cam synchronisation on start-up feature disabled
• Some Oxygen sensor diagnostics disabled.
In addition, the ECM will store a relevant fault code and capture the input signal supplied by the
engine coolant temperature sensor, the engine load calculation and the engine speed at the
time of failure. TestBook/T4 will display the live readings from the CMP sensor.
Ambient Barometric Pressure Sensor
The ECM incorporates an integral ambient barometric pressure sensor. This internal sensor is
supplied with a 5V feed and returns a linear voltage of between 2.4 and 4.5 Volts. This
represents the barometric pressure.
The system monitors barometric pressure for the following reasons:
• The barometric pressure along with the calculated air mass provides additional correction
for refining injection “ON” time
• The value provides a base value for the ECM to calculate the air mass being injected into
the exhaust system by the secondary air injection system. This correction factor changes
the secondary air injection “ON” time which in turn optimizes the necessary air flow into the
exhaust system
• The signal is used to recognize down hill driving and to postpone the start of evaporative
emission leakage diagnosis.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is located front of the engine, adjacent to the thermostat housing. The sensor
incorporates two Negative Temperature Coefficient (NTC) thermistors and four electrical
connections. One set of connections are used by the ECM while the other set are used by the
instrument pack temperature gauge.
ECT Sensor
Each thermistor used forms part of a voltage divider circuit operating with a regulated 5 V feed
and an earth.
184
BOSCH ME 7.2 ENGINE MANAGEMENT
The signal supplied by the ECT sensor is critical to many fuel and ignition control strategies.
Therefore, the ECM incorporates a complex ECT sensor default strategy, which it implements in
the event of failure. The ECM uses a software model, based on the time the engine has been
running and the air intake temperature, to provide a changing default value during the engine
warm-up. When the software model calculates the coolant temperature has reached 60 °C (140
°F), a fixed default value of 85 °C (185 °F) is adopted for the remainder of the ignition cycle. The
software model also forms part of the sensor diagnostics: if there is too great a difference
between the temperatures from the sensor input and the software model, for more than 2.54
seconds, the ECM concludes there is a fault with the sensor input.
The following symptoms may be noticeable in the event of an ECT sensor failure:
•
•
•
•
The MIL lamp illuminated
Poor engine hot and cold start
Instrument pack engine overheat warning lamp illuminated
Excessively hot or cold reading on the temperature gauge.
At the time of a failure, the ECM will also store details of the engine speed, engine load and
intake air temperature in its memory. This information is stored to aid diagnosis of the fault.
Knock Sensors
Two knock sensors are located on each cylinder block between the first and second and third
and fourth cylinders of each cylinder bank. The knock sensors produce a voltage signal in
proportion to the amount of mechanical vibration generated at each ignition point. Each sensor
monitors two cylinders in the related cylinder bank.
Electric Throttle System
185
BOSCH ME 7.2 ENGINE MANAGEMENT
Knock Sensor
The knock sensors incorporate a piezo-ceramic crystal. This crystal produces a voltage
whenever an outside force tries to deflect it, (i.e. exerts a mechanical load on it). When the
engine is running, the compression waves in the material of the cylinder block, caused by the
combustion of the fuel/air mixture within the cylinders, deflect the crystal and produce an output
voltage signal. The signals are supplied to the ECM, which compares them with `mapped'
signals stored in memory. From this, the ECM can determine when detonation occurs on
individual cylinders. When detonation is detected, the ECM retards the ignition timing on that
cylinder for a number of engine cycles, then gradually returns it to the original setting.
Care must be taken at all times to avoid damaging the knock sensors, but particularly during
removal and fitting procedures. The recommendations regarding torque and surface
preparation must be adhered to. The torque applied to the sensor and the quality of the surface
preparation both have an influence over the transfer of mechanical noise from the cylinder block
to the crystal.
The ECM uses the signals supplied by the knock sensors, in conjunction with the signal it
receives from the camshaft sensor, to determine the optimum ignition point for each cylinder.
The ignition point is set according to pre-programmed ignition maps stored within the ECM. The
ECM is programmed to use ignition maps for 95 RON premium specification fuel. It will also
function on 91 RON regular specification fuel but without adaptions. If the only fuel available is
of poor quality, or the customer switches to a lower grade of fuel after using a high grade for a
period of time, the engine may suffer slight pre-ignition for a short period. This amount of preignition will not damage the engine. This situation will be evident while the ECM learns and then
modifies its internal mapping to compensate for the variation in fuel quality. This feature is called
adaption. The ECM has the capability of adapting its fuel and ignition control outputs in
response to several sensor inputs.
The ECM will cancel closed loop control of the ignition system if the signal received from either
knock sensor becomes implausible. In these circumstances the ECM will default to a safe
ignition map. This measure ensures the engine will not become damaged if low quality fuel is
used. The MIL lamp will not illuminate, although the driver may notice that the engine 'pinks' in
some driving conditions and displays a slight drop in performance and smoothness.
186
BOSCH ME 7.2 ENGINE MANAGEMENT
When a knock sensor fault is stored, the ECM will also store details of the engine speed, engine
load and the coolant temperature.
Mass Air Flow/Air Intake Temperature (MAF/IAT) Sensor
The MAF/IAT sensor is located in the air intake ducting, between the air cleaner and the throttle
body. The sensor outputs intake air flow and temperature signals to the ECM to enable
calculation of the mass of the air entering the engine.
In addition to the air flow and temperature outputs, a regulated 5 V feed and an earth are
connected between the sensor and the ECM, and the sensor receives a battery power feed
from the main relay.
Air flow:
The air flow signal is produced from a hot film element in the sensor. The film is connected
between the 5 V feed and the air flow output to the ECM. The film is also heated by the battery
power feed and cooled by the air flow into the engine. The greater the air flow, the greater the
cooling effect and the lower the electrical resistance across the sensor. So the air flow output
voltage varies with changes in air flow and, from voltage/air flow maps stored in memory, the
ECM determines the mass of air entering the engine.
Air intake temperature:
The air intake temperature signal is produced by a NTC thermistor connected between the 5 V
feed and earth to complete a voltage divider circuit. The ECM monitors the voltage drop across
the thermistor and, from voltage/temperature maps stored in memory, determines the
temperature of the intake air.
The MAF/IAT sensor is sensitive to sudden shocks and changes in its orientation. It should,
therefore, be handled carefully. It is also important that the intake ducting between the air
cleaner and the throttle body is not altered in diameter or modified in any way. The air mass flow
meter contains electronic circuitry, so never attempt to supply it directly from the battery. The
terminals have a silver coating to provide a superior quality of connection over many years. If, at
any time, a probe is used to measure the output directly from the sensor, then care must be
taken to ensure this coating is not damaged.
Electric Throttle System
187
BOSCH ME 7.2 ENGINE MANAGEMENT
MAF/IAT Sensor
If the air flow signal fails the ECM adopts a default value for air flow volume based on throttle
position and engine speed. The following engine symptoms will be noticeable:
• The engine speed might 'dip' before the default strategy enables continued running
• The engine may be difficult to start and prone to stalling
• The overall performance of the engine will be adversely affected (throttle response in particular)
• Exhaust emissions will be out of tolerance, because the air/fuel ratio value is now assumed,
not calculated; no closed loop fuelling
• Idle speed control disabled, leading to rough idle and possible engine stall.
At the time of failure, the ECM will store details of the engine speed, coolant temperature and
throttle angle.
If the intake air temperature signal fails, the ECM adopts a default value of 45 °C. This default
value is then used within all the calculations involving intake air temperature. The effect on the
vehicle of a failed air temperature signal will not be so noticeable to the driver, who may notice a
reduction in engine performance when operating the vehicle at high altitudes or in hot ambient
temperatures. The occurrence of this fault will also disable fuelling adaptions.
The ECM will store details of the engine speed, engine load and battery voltage when this fault
is first detected.
Heated Oxygen Sensors (HO2S)
The HO2S provide feedback signals to the ECM to enable closed loop control of the Air Fuel
Ratio (AFR). Four HO2S are installed, one pre-catalyst and one post-catalyst per cylinder bank.
Each HO2S produces an output voltage which is inversely proportional to the oxygen content of
the exhaust gases.
188
BOSCH ME 7.2 ENGINE MANAGEMENT
HO2S
Each HO2S consists of a zirconium sensing element with a gas permeable ceramic coating on
the outer surface. The outer surface of the sensing element is exposed to the exhaust gas and
the inner surface is exposed to ambient air. The difference in the oxygen content of the two
gases produces an electrical potential difference across the sensing element. The voltage
produced depends on the differential between the two oxygen contents. When the AFR is
Lambda 1 (i.e. stoichiometric AFR of 14.7:1 by mass) the voltage produced is approximately
450 mV. With a lean mixture of Lambda 1.2, the higher oxygen content of the exhaust gases
results in a voltage of approximately 100 mV. With a rich mixture of Lambda 0.8, the lower
oxygen content of the exhaust gases results in a voltage of approximately 900 mV.
The ECM monitors the effect of altering the injector pulse widths using the information supplied
by the two HO2S. Injector pulse width is the length of time the injector is energized, which
determines how much fuel is injected. The response time is such that under certain driving
conditions, the ECM can assess individual cylinder contributions to the total exhaust emissions.
This enables the ECM to adapt the fuelling strategy on a cylinder by cylinder basis, i.e. inject the
precise amount of fuel required by each individual cylinder at any given time.
Electric Throttle System
189
BOSCH ME 7.2 ENGINE MANAGEMENT
HO2S Principle of Operation
A
Ambient air
2
Electrodes
B
Exhaust gases
3
Zirconium oxide
1
Protective ceramic coating
HO2S Output
A
Output, mV
2
Lean AFR
B
AFR, lambda
3
Rich AFR
1
Lambda window
The ECM continuously checks the signals supplied by the HO2S for plausibility. If it detects an
implausible signal, the ECM stores a relevant fault code and details of engine speed, engine
load and the HO2S signal voltage. The ECM requires the HO2S signals to set most of its
adaptions. Failure of an HO2S results in most of these adaptions resetting to their default
values. This, in turn, results in loss of engine refinement. The engine may exhibit poor idle
characteristics and emit a strong smell of rotten eggs from the exhaust (caused by an increase
in hydrogen sulphide).
The efficiency of the HO2S slowly deteriorates with use and must be periodically replaced
(currently every 120,000 miles, but refer to the maintenance schedules for the latest service
replacement period). The ECM is able to detect this steady deterioration from the HO2S
signals. If a sensor deteriorates beyond a predetermined threshold, the ECM stores a fault code
and captures details of the engine speed, engine load and battery voltage.
190
BOSCH ME 7.2 ENGINE MANAGEMENT
The HO2S needs a high operating temperature to work effectively. To ensure a suitable
operating temperature is reached as soon as possible, each sensor incorporates a heating
element inside the ceramic tip. This element heats the HO2S to a temperature greater than 350
°C (662 °F). The heating rate (the speed at which the temperature rises) is carefully controlled
by the ECM to prevent thermal shock to the ceramic material. The ECM supplies a Pulse Width
Modulated (PWM) supply to the heater elements to control the rate at which the HO2S
temperature is increased. The HO2S are heated during engine warm-up and again after a
period of engine idle.
The ECM monitors the state of the heating elements by calculating the amount of current
supplied to each sensor during operation. If the ECM identifies that the resistance of either
heating element is too high or too low, it will store a fault code, the engine speed, coolant
temperature and the battery voltage.
HO2S are very sensitive devices. They must be handled carefully at all times. Failure to handle
correctly will result in a very short service life, or non-operation. HO2S are threads coated with
an anti-seize compound prior to installation. Care should be taken to avoid getting this
compound on the sensor tip. If the sensor needs to be removed and refitted, a small amount of
anti-seize compound should be applied (see workshop manual for details).
Radiator Outlet Temperature Sensor
The ECM uses an additional engine coolant temperature sensor located in the radiator outlet.
The sensor monitors the temperature of the coolant leaving the radiator for precise activation of
the auxiliary fan. The sensor is an NTC thermistor type. The signal is used by the ECM to
activate the auxiliary fan when the engine coolant temperature leaving the radiator is in the
range of 80 to 104 °C (176 to 219 °F).
Fuel Level Signal
The ECM monitors the contents of the fuel tank as part of the misfire detection strategy. If a
misfire occurs while a low fuel level exists, the ECM stores an additional fault code to indicate
that fuel starvation resulting from fuel slosh is a possible cause of the misfire. On New Range
Rover, the low fuel level signal is internally generated by the ECM, from a CAN signal via the
instrument pack.
Electric Throttle System
191
BOSCH ME 7.2 ENGINE MANAGEMENT
Vehicle Speed Signal
The ECM receives the vehicle speed signal from the ABS ECU. The ECM uses this signal
within its calculations for idle speed control. The signal is transmitted at 8000 pulses/mile and is
the average of the road speed signals from all four wheel speed sensors. The ABS ECU outputs
the vehicle speed signal to the EAT ECU on the CAN bus.
Rough Road Signal
When the vehicle is travelling over a rough road surface the engine crankshaft is subjected to
torsional vibrations caused by mechanical feedback from the road surface through the
transmission. To prevent misinterpretation of these torsional vibrations as a misfire, the ECM
calculates a rough road level by monitoring individual wheel speeds from the ABS ECU on the
CAN bus. The ECM determines the quality of the road surface by monitoring a CAN signal from
the ABS ECU, which modulates the duty cycle of the signal in response to variations between
ABS sensor inputs. Misfire monitoring is restored when the quality of the road surface improves
again.
If there is a fault with the CAN data, the ECM defaults to permanent misfire monitoring.
A/C Request Signals
Because of the loads imposed on the engine when the air conditioning system operates, the
ECM is included in the control loop for the compressor and the cooling fans. If it becomes
necessary to limit or reduce the load on the engine, the ECM can then prevent or discontinue
operation of the air conditioning compressor.
Automatic Gearbox Information
Information sent to and from the EAT ECU is transmitted on the CAN bus.
The ECM requires information on gear position to calculate the likely engine load during
acceleration and deceleration conditions. The ECM also disables the misfire detection function
whenever low range is selected. The ECM receives this information from the transfer box ECU
on the CAN Bus.
There are several possible fault codes associated with the CAN bus and the validity of the
messages exchanged between the ECM and the EAT ECU. In most cases, the ECM will store
engine speed, engine coolant temperature and details of the battery voltage at the time a CAN
fault is detected.
If the EAT ECU detects a gearbox fault, it requests the ECM to illuminate the MIL in the
instrument pack and to store freeze frame data.
Ignition Switch
The ignition switch signal enables the ECM to detect if the ignition is on or off. The signal is a
power feed that is connected to the ECM while the ignition switch is positions II and III. On the
New Range Rover, the power feed comes from the ignition relay in the engine compartment
fuse box.
192
BOSCH ME 7.2 ENGINE MANAGEMENT
When it first receives the signal, the ECM 'wakes-up' and initiates a power-up sequence to
enable engine starting and operation. The power-up sequence includes energising the main
relay, which supplies the main power feed to the ECM, energising the fuel pump relay and
initiating a self check of the engine management system.
When it detects the ignition has been turned off, the ECM stops activating the fuel injectors and
ignition coil, to stop the engine, and de-energizes the fuel pump relay, but keeps the main relay
energized while it performs a power down sequence. During the power down sequence the
ECM records the engine sensor values required for a quick-start function to operate the next
time the engine is cranked. At the end of the power down sequence, the ECM de-energizes the
main relay to switch itself off.
System Outputs
The ECM receives and processes the input information previously described and modifies the
fuelling and the ignition points for each cylinder accordingly. The ECM will also supply output
information to other vehicle systems.
The ECM drives the following components:
•
•
•
•
•
•
•
•
•
Fuel injectors
Ignition coils
Main relay and fuel pump relay
Tank Leakage Detection (where fitted)
Secondary Air Injection Pump
Secondary Air Injection valve
VCC Valves
Electrically heated thermostat
Air conditioning compressor (relay drive).
The ECM provides other systems with information regarding the:
•
•
•
•
•
•
Engine speed
Driver demand
ATC request
Automatic Transmission
Fuel used
Auxiliary cooling fan.
Ignition Coils
The ME 7.2 EMS utilizes plug top coils which are mounted directly on top of the spark plug.
System Outputs
193
BOSCH ME 7.2 ENGINE MANAGEMENT
Ignition Coils
Ignition related faults are indirectly monitored via misfire detection. The are no specific checks
of the primary circuits.
Fuel Injectors
An electromagnetic, top feed fuel injector is installed in each cylinder inlet tract of the inlet
manifolds. A common fuel rail supplies the injectors with fuel from a returnless fuel delivery
system. The fuel in the fuel rail is maintained at 3.5 bar (50.75 lbf.in 3) above inlet manifold
pressure by a pressure regulator incorporated into the fuel filter. A Schraeder valve is installed
in the fuel rail, to the rear of injector No. 7, to enable the fuel pressure to be checked.
Fuel Rail and Injectors
Each injector contains a solenoid operated needle valve which is closed while the solenoid
winding is de-energized. The solenoid winding is connected to a power feed from the main relay
and to an earth through the ECM. The ECM switches the earth to control the opening and
closing of the needle valve (injector 'firing'). While the needle valve is open, fuel is sprayed into
the cylinder inlet tract onto the back of the inlet valves. The ECM meters the amount of fuel
injected by adjusting the time that the needle valve is open (injector pulse width).
194
BOSCH ME 7.2 ENGINE MANAGEMENT
Each injector is sealed with two 'O' rings, which should be renewed whenever an injector is
refitted to an engine. A small amount of engine oil can be applied to the 'O' rings to aid
installation. No other form of lubrication should be used.
Fuel Injector
Measuring the electrical resistance of the solenoid winding enables an assessment to be made
of the serviceability of an injector. Nominal resistance of the solenoid winding is 14.5 ± 0.7 Ω at
20 °C (68 °F).
The ECM can detect electrical inconsistencies within each injector. It can also detect, via
feedback from the HO2S, mechanical faults such as blockage or leakage. The ECM will store a
relevant fault code in these circumstances. The ECM will also store the engine speed, engine
load and details of either the battery voltage, engine coolant temperature or intake air
temperature. The precise details stored depend on the exact nature of the fault detected.
TestBook/T4 will also display data regarding injector operation via its live readings. Care must
be taken when analysing this data, as the precise timings will vary considerably. Individual
timings will be affected by any current engine load.
Main Relay
The ECM controls its own power supply, via the main relay in the engine compartment fusebox.
When the ignition is turned to position II, the ECM provides a ground to the main relay coil. The
main relay then energizes and connects the main power feed to the ECM. The ECM controls
the main relay, and therefore its own power supply, so that when the ignition is turned off it can
follow the power-down sequence, during which it records values from various sensors and
writes adaptions into its memory, etc. The last action the ECM carries out before completing its
power-down sequence is to turn off the main relay. This will occur approximately 7 seconds
after the ignition has been switched off, as long as the coolant temperature is not rising. For
vehicles with tank module leak detection and under some vehicle system fault conditions, this
period could be extended up to 20 minutes.
Failure of the main relay will result in the engine failing to start. The engine will stop immediately
if the main relay fails while the engine is running.
System Outputs
195
BOSCH ME 7.2 ENGINE MANAGEMENT
Fuel Pump Relay
The ECM controls operation of the fuel pump via the fuel pump relay in the rear fusebox. The
ECM switches the relay coil to earth to energize the relay when the ignition is first turned to
position II. The relay remains energized during engine cranking and while the engine is running,
but will be de-energized after approximately 2 seconds if the ignition switch remains in position
II without the engine running.
A fuel cut-off function is incorporated into the ECM to de-energize the fuel pump in a collision.
The cut off function is activated by a signal from the SRS DCU in the event of an airbag
activation. The ECM receives an airbag activation signal from the SRS DCU on the CAN Bus.
The fuel cut-off function can only be reset by using TestBook/T4.
The ECM monitors the state of the wiring to the coil winding within the fuel pump relay. The
ECM will store relevant fault codes if the ECM detects a problem. The ECM is not able to
assess the state of the fuel pump circuit because it is isolated by the function of the relay.
However, if the fuel pump circuit fails, or the pump fails to deliver sufficient fuel (while the fuel
level is above the minimum level), the ECM will store adaptive faults as it tries to increase the
air/fuel ratio by increasing the pulse width of the injectors.
Failure of the fuel pump relay will result in the engine failing to start. If the fuel pump fails while
the engine is running, the symptoms will be engine hesitation and engine misfire. These
symptoms will worsen progressively until the engine stops. The ECM will store several fault
codes under this condition.
Electrically Heated Thermostat
The electrically heated thermostat is used to regulate the engine coolant temperature. The
thermostat regulates the coolant temperature depending upon engine load and vehicle speed.
This allows the engine coolant temperature to be raised when the engine is operating at part
load. Raising the coolant temperature while the engine is at part load has a beneficial effect on
fuel consumption and emissions.
If a conventional thermostat with higher constant operating temperature is used, poor response
when accelerating and in traffic could result.
The thermostat is controlled by the ECM is response to engine load against a 'map' stored
within the ECM.
The map is based upon the following inputs:
•
•
•
•
•
Engine load
Engine speed
Vehicle speed
Intake air temperature
Coolant temperature.
The thermostat unit is a one piece construction comprising the thermostat, thermostat housing
and heater element. The housing is of a die-cast aluminium. The electrical connection for the
heater element is housed in the body. The heater element is an expanding (wax) element.
196
BOSCH ME 7.2 ENGINE MANAGEMENT
Heated Thermostat
The thermostat is set to open when the coolant temperature reaches 103 °C (217 °F) at the
thermostat. Once the coolant has passed through the engine its temperature is approximately
110 °C (230 °F) at the engine temperature sensor.
If the ECM starts to regulate the system the ECM supplies an earth path for the heater element
in the thermostat. This causes the element to expand and increase the opening dimension of
the thermostat.
The warmer the element the sooner the thermostat opens and the lower the resulting coolant
temperature is. The thermostat regulates the coolant temperature in the range 80 to 103 °C
(176 to 217 °F). The expanding element in the thermostat is heated to a higher temperature
than the surrounding coolant to generate the correct opening aperture. Should the coolant
temperature exceed 113 °C (235 °F) the electrically heated thermostat is activated
independently of the prevailing engine parameters.
Should the heated thermostat fail, (fault codes will be stored in the ECM) the EMS will ensure
the safe operation of the engine and the thermostat will operate as a conventional unit.
ECM Adaptions
The ECM has the ability to adapt the values it uses to control certain outputs. This capability
ensures the EMS can meet emissions legislation and improve the refinement of the engine
throughout its operating range.
The components which have adaptions associated with them are:
•
•
•
•
•
•
The IACV
The APP sensor
The HO2S
The MAF/IAT sensor
The CKP sensor
Electric throttle body.
ECM Adaptions
197
BOSCH ME 7.2 ENGINE MANAGEMENT
HO2S and MAF/IAT Sensor
There are several adaptive maps associated with the fuelling strategy. Within the fuelling
strategy the ECM calculates short-term adaptions and long term adaptions. The ECM will
monitor the deterioration of the HO2S over a period of time. It will also monitor the current
correction associated with the sensors.
The ECM will store a fault code in circumstances where an adaption is forced to exceed its
operating parameters. At the same time, the ECM will record the engine speed, engine load and
intake air temperature.
CKP Sensor
The characteristics of the signal supplied by the CKP sensor are learned by the ECM. This
enables the ECM to set an adaption and support the engine misfire detection function. Due to
the small variation between different flywheels and different CKP sensors, the adaption must be
reset if either component is renewed, or removed and refitted. It is also necessary to reset the
flywheel adaption if the ECM is renewed or replaced.
The ECM supports four flywheel adaptions for the CKP sensor. Each adaption relates to a
specific engine speed range. The engine speed ranges are detailed in the table below:
Adaptation
1
2
3
4
Engine Speed, rev/
min
1800 - 3000
3001 - 3800
3801 - 4600
4601 - 5400
To set the flywheel adaptions, follow the procedure detailed below. This procedure should be
carried out in an appropriate area off the public highway. TestBook/T4 must be connected
throughout this procedure. The adaptive speed settings must be read from TestBook/T4 while
the vehicle is moving at speed.
1 Use TestBook/T4 to clear any adaptions currently set.
2 With the engine warm (> 86 °C (187 °F)), select 2nd gear high range.
3 Accelerate the vehicle until the engine speed reaches the limiter.
4 Release the throttle and allow the vehicle to decelerate until the engine idle speed is
reached.
5 Check that one of the speed range adaptions has been set (read this from TestBook/T4).
6 Repeat the above procedure until all four adaptions are set
When all four adaptions have been set, check that the ECM has not recorded any misfire
detection faults. If it has, then clear the memory of the misfire fault codes.
198
BOSCH ME 7.2 ENGINE MANAGEMENT
It may not be possible to reset adaption number 4 if the ECM has already been programmed
with a value. Due to the nature of the procedure and the self learn capacity of the ECM, if
adaption number 4 does not reset, it is permissible to leave this adaption and let the ECM learn
it during normal vehicle usage.
Misfire Detection
Legislation requires that the ECM must be able to detect the presence of an engine misfire. It
must be able to detect misfires at two separate levels. The first level is a misfire that could lead
to the vehicle emissions exceeding 1.5 times the Federal Test Procedure (FTP) requirements
for the engine. The second level is a misfire that may cause catalyst damage.
The ECM monitors the number of misfire occurrences within two engine speed ranges. If the
ECM detects more than a predetermined number of misfire occurrences within either of these
two ranges, over two consecutive journeys, the ECM will record a fault code and details of the
engine speed, engine load and engine coolant temperature. In addition, the ECM monitors the
number of misfire occurrences that happen in a 'window' of 200 engine revolutions. The misfire
occurrences are assigned a weighting according to their likely impact on the catalysts. If the
number of misfires exceeds a certain value, the ECM stores catalyst-damaging fault codes,
along with the engine speed, engine load and engine coolant temperature.
The signal from the crankshaft position sensor indicates how fast the poles on the flywheel are
passing the sensor tip. A sine wave is generated each time a pole passes the sensor tip. The
ECM can detect variations in flywheel speed by monitoring the sine wave signal supplied by the
crankshaft position sensor.
By assessing this signal, the ECM can detect the presence of an engine misfire. At this time, the
ECM will assess the amount of variation in the signal received from the crankshaft position
sensor and assigns a roughness value to it. This roughness value can be viewed within the real
time monitoring feature, using TestBook/T4. The ECM will evaluate the signal against a number
of factors and will decide whether to count the occurrence or ignore it. The ECM can assign a
roughness and misfire signal for each cylinder, (i.e. identify which cylinder is misfiring).
TestBook/T4 Diagnostics
The ECM stores faults as Diagnostic Trouble Codes (DTC), referred to as 'P' codes. The 'P'
codes are defined by OBD legislation and, together with their associated environmental and
freeze frame data, can be read using a third party scan tool or TestBook/T4. TestBook/T4 can
also read real time data from each sensor, the adaptive values currently being employed and
the current fuelling, ignition and idle settings.
Several different drive cycles are defined by OBD legislation for fault diagnosis. Each drive
cycle is a precise routine which the engine or vehicle must undergo to produce the conditions
that enable the ECM to perform diagnostic routines. TestBook/T4 can be used to view the status
and results of the diagnostic routines performed by the ECM. When a fault code is stored, it will
indicate, via TestBook/T4, the drive cycle required to verify a repair.
TestBook/T4 Diagnostics
199
BOSCH ME 7.2 ENGINE MANAGEMENT
The ECM only records a fault after it has occurred on more than one drive cycle. This fault
strategy is referred to as debouncing. When it is first detected, a fault is stored as a temporary
fault. If the fault recurs within the next 40 warm-up cycles, the fault is stored as a permanent
fault and freeze frame data for the second occurrence is recorded. If the fault does not recur
within the next 40 warm-up cycles, the ECM deletes the temporary fault from memory.
The ECM illuminates the MIL when requested to do so by the EAT ECU, to perform a bulb
check when the ignition is switched on, and for any emissions related fault. There is no MIL
illumination for non emission related engine management faults.
Resetting the adaptions will clear all adaptions from the ECM memory.
Engine Management P Codes
P Code No.
0010
0011
Component/Signal
RH bank CMP sensor
RH bank CMP sensor
0012
0020
0021
RH bank CMP sensor
LH bank CMP sensor
LH bank CMP sensor
0022
0030
0031
0032
0036
0037
0038
0050
0051
0052
0056
0057
0058
0102
0103
0106
0107
0108
LH bank CMP sensor
RH bank front HO2S heater circuit
RH bank front HO2S heater circuit
RH bank front HO2S heater circuit
RH bank rear HO2S heater circuit
RH bank rear HO2S heater circuit
RH bank rear HO2S heater circuit
LH bank front HO2S heater circuit
LH bank front HO2S heater circuit
LH bank front HO2S heater circuit
LH bank rear HO2S heater circuit
LH bank rear HO2S heater circuit
LH bank rear HO2S heater circuits
MAF sensor signal
MAF sensor signal
ECM internal ambient pressure
sensor
ECM internal ambient pressure
ECM internal ambient pressure
0112
0113
IAT sensor
IAT sensor
200
Fault Description
Signal malfunction
Timing over-advanced or system
performance
Timing over-retarded
Signal malfunction
Timing over-advanced or system
performance
Timing over-retarded
Circuit intermittent
Short circuit to ground
Short circuit to battery
Circuit intermittent
Short circuit to ground
Short circuit to battery
Circuit intermittent
Short circuit to ground
Short circuit to battery
Circuit intermittent
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Performance problem
Short circuit to ground
Open circuit or short circuit to
battery
Short circuit to ground
Open circuit or short circuit to
battery
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
0114
0116
0117
0118
Component/Signal
Ambient temperature input
ECT sensor
ECT sensor
ECT sensor
0120
0121
0122
APP sensor switch A
APP sensor switch A
APP sensor switch A
0123
0125
APP sensor switch A
ECT sensor
0128
Thermostat monitoring sensor
0130
0131
0132
0133
0134
0135
0136
0137
0138
0139
0140
0141
0150
0151
0152
0153
0154
0155
0156
0157
0158
0159
0160
0161
0171
0172
RH bank front HO2S signal
RH bank front HO2S signal
RH bank front HO2S signal
RH bank front HO2S signal
RH bank front HO2S signal
RH bank front HO2S heater circuit
RH bank rear HO2S signal
RH bank rear HO2S signal
RH bank rear HO2S signal
RH bank rear HO2S signal
RH bank rear HO2S signal
RH bank rear HO2S heater circuit
LH bank front HO2S signal
LH bank front HO2S signal
LH bank front HO2S signal
LH bank front HO2S signal
LH bank front HO2S signal
LH bank front HO2S heater circuit
LH bank rear HO2S signal
LH bank rear HO2S signal
LH bank rear HO2S signal
LH bank rear HO2S signal
LH bank rear HO2S signal
LH bank rear HO2S heater circuit
RH bank lambda control
RH bank lambda control
TestBook/T4 Diagnostics
Fault Description
Fault data received
Signal implausible
Short circuit to ground
Open circuit or short circuit to
battery
Implausible
Range/ Performance problem
Open circuit or short circuit to
ground
Short circuit to battery
Insufficient coolant temperature for
closed loop control
Low coolant temperature ñ
thermostat stuck open
Circuit malfunction
Short circuit to ground
Short circuit to battery
Slow response
No activity
Circuit malfunction
Circuit malfunction
Short circuit to ground
Short circuit to battery
Slow response
No activity
Circuit malfunction
Circuit malfunction
Short circuit to ground
Short circuit to battery
Slow response
No activity
Circuit malfunction
Circuit malfunction
Short circuit to ground
Short circuit to battery
Slow response
No activity
Malfunction
Fuelling too lean
Fuelling too rich
201
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
0174
0175
0201
0202
0203
0204
0205
0206
0207
0208
0221
0222
Component/Signal
LH bank lambda control
LH bank lambda control
Fuel injector 1
Fuel injector 2
Fuel injector 3
Fuel injector 4
Fuel injector 5
Fuel injector 6
Fuel injector 7
Fuel injector 8
APP sensor switch B
APP sensor switch B
0223
0231
0232
0233
0261
0262
0264
0265
0267
0268
0270
0271
0273
0274
0276
0277
0279
0280
0282
0283
0300
0301
0302
0303
0304
0305
0306
APP sensor switch B
Fuel pump motor drive
Fuel pump motor drive
Fuel pump motor drive
Fuel injector 1
Fuel injector 1
Fuel injector 2
Fuel injector 2
Fuel injector 3
Fuel injector 3
Fuel injector 4
Fuel injector 4
Fuel injector 5
Fuel injector 5
Fuel injector 6
Fuel injector 6
Fuel injector 7
Fuel injector 7
Fuel injector 8
Fuel injector 8
Misfire detection
Misfire detection
Misfire detection
Misfire detection
Misfire detection
Misfire detection
Misfire detection
202
Fault Description
Fuelling too lean
Fuelling too rich
Open circuit
Open circuit
Open circuit
Open circuit
Open circuit
Open circuit
Open circuit
Open circuit
Range/ Performance problem
Open circuit or short circuit to
ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Circuit fault
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Random/Multiple cylinder misfire
Cylinder 1 misfire
Cylinder 2 misfire
Cylinder 3 misfire
Cylinder 4 misfire
Cylinder 5 misfire
Cylinder 6 misfire
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
0307
0308
0324
0327
0328
0332
0333
0335
0340
0342
0343
0345
0347
0348
0370
0411
0412
0413
0414
0418
0420
0430
0442
0443
0444
0445
0455
0456
0461
0462
0463
0464
0491
0492
0500
0501
Component/Signal
Misfire detection
Misfire detection
Knock sensors
RH bank knock sensor 1
RH bank knock sensor 1
LH bank knock sensor 3
LH bank knock sensor 3
CKP sensor
RH bank CMP sensor
RH bank CMP sensor
RH bank CMP sensor
LH bank CMP sensor
LH bank CMP sensor
LH bank CMP sensor
Reference mark detection
Fault Description
Cylinder 7 misfire
Cylinder 8 misfire
Control system error
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Signal implausible
Signal implausible
Short circuit to ground
Short circuit to battery
Signal implausible
Short circuit to ground
Short circuit to battery
Timing reference high resolution
signal A
SAI vacuum solenoid valve
Incorrect flow detected
SAI vacuum solenoid valve drive
Circuit malfunction
SAI vacuum solenoid valve drive
Open circuit
SAI vacuum solenoid valve drive
Short circuit
SAI air injection pump relay
Open circuit
RH bank catalytic converter
Efficiency below threshold/light off
too long
LH bank catalytic converter
Efficiency below threshold/light off
too long
EVAP system
Minor leak (1.0 mm or less)
Purge valve drive
Circuit malfunction
Purge valve drive
Open circuit
Purge valve drive
Short circuit to battery or ground
EVAP system
Major leak (more than 1.0 mm)
EVAP system
Minor leak (0.5 mm or less)
Fuel tank level signal
Range/Performance problem
Fuel tank level signal
Short circuit to ground
Fuel tank level signal
Short circuit to battery
Fuel tank level signal
Circuit intermittent
SAI system
Malfunction on RH bank
SAI system
Malfunction on LH bank
Vehicle speed signal
Signal implausible
Rough road detection vehicle speed Intermittent, erratic or high
signal
TestBook/T4 Diagnostics
203
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
0503
0512
0530
0532
0533
0561
0562
0563
0571
0604
0605
0606
0615
0616
0617
0634
0650
Component/Signal
Rough road detection vehicle speed
signal
Comfort start
A/C refrigerant pressure sensor
A/C refrigerant pressure sensor
A/C refrigerant pressure sensor
Battery voltage monitor
Battery voltage monitor
Battery voltage monitor
Brake lights switch
ECM self test
ECM self test
ECM self test
Comfort start relay drive
Comfort start relay drive
Comfort start relay drive
ECU internal temperature
MIL output drive
0660
0661
Manifold valve output drive
Manifold valve output drive
0662
0691
0692
0693
0704
1000
Manifold valve output drive
Engine cooling fan control
Engine cooling fan control
Engine cooling fan control
A/C compressor clutch switch
DMTL pump motor drive
1102
1117
1118
Throttle position to mass air flow
plausibility not active
Throttle position to mass air flow
plausibility not active
Thermostat monitoring sensor
Thermostat monitoring sensor
1120
1121
1122
1123
1129
APP sensor
APP sensor 1
APP sensor 1
APP sensor 1
HO2S
1103
204
Fault Description
Range/Performance
Request circuit malfunction
Signal fault
Short circuit to ground
Short circuit to battery
System voltage unstable
System voltage low
System voltage high
Cruise control/brake switch circuit A
RAM error
ROM error
Processor fault
Open circuit
Short circuit to ground
Short circuit to battery
ECU temperature high
Open circuit, or short circuit to
ground or battery
Control circuit malfunction
Open circuit or short circuit to
ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Circuit intermittent
Input circuit malfunction
Intermittent or short circuit to ground
or battery
Air mass too small
Air mass too large
Short circuit to ground
Open circuit or short circuit to
battery
Implausible signals
Range/ Performance problem
Short circuit to ground
Short circuit to battery
Swapped sensors (LH to RH)
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
1161
1162
1163
1164
1170
1171
1172
1173
1174
1175
1221
1222
1223
1300
1301
1327
1328
1332
1333
1413
1414
1450
1451
1452
1453
1454
1455
1456
1481
1482
Component/Signal
RH bank lambda control
RH bank lambda control
LH bank lambda control
LH bank lambda control
RH bank front HO2S signal
RH bank lambda control
RH bank lambda control
LH bank front HO2S signal
LH bank lambda control
LH bank lambda control
APP sensor 2
APP sensor 2
APP sensor 2
Misfire detection
Misfire detection
RH bank knock sensor 2
RH bank knock sensor 2
LH bank knock sensor 4
LH bank knock sensor 4
SAI air injection pump relay
SAI air injection pump relay
DMTL pump motor
DMTL pump motor
DMTL pump motor
DMTL pump motor
DMTL changeover valve drive
DMTL changeover valve drive
DMTL changeover valve drive
DMTL heater output drive
DMTL heater output drive
1483
1488
1489
1490
1522
1523
1524
1525
1526
DMTL heater output drive
DMTL pump motor drive
DMTL pump motor drive
DMTL pump motor drive
Plausibility MSR intervention
RH bank VCC solenoid valve
RH bank VCC solenoid valve
RH bank VCC solenoid valve
LH bank VCC solenoid valve
TestBook/T4 Diagnostics
Fault Description
Adaption per ignition too small
Adaption per ignition too large
Adaption per ignition too small
Adaption per ignition too large
Fuel trim malfunction
Adaption over time too large
Adaption over time too small
Fuel trim malfunction
Adaption over time too large
Adaption over time too small
Range/ Performance problem
Short circuit to ground
Short circuit to battery
Catalyst damaging misfire
Multiple cylinder misfire
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Short circuit to ground
Short circuit to battery
Reference current above limit
Reference current below limit
Reference current unstable
Changeover valve stuck
Short circuit to battery
Short circuit to ground
Open circuit
Signal intermittent
Open circuit or short circuit to
ground
Short circuit to battery
Open circuit
Short circuit to ground
Short circuit to battery
No activity
Short circuit to ground
Short circuit to battery
Open circuit
Open circuit
205
BOSCH ME 7.2 ENGINE MANAGEMENT
P Code No.
1527
1528
1614
1615
1616
1619
1620
1621
1623
1624
1626
1630
1631
1632
1633
1634
1635
1638
1639
1645
1646
1647
1651
1659
1660
1666
1672
1673
1674
1693
1694
1700
1709
206
Component/Signal
LH bank VCC solenoid valve
LH bank VCC solenoid valve
Electric thermostat heater drive
Electric thermostat heater drive
Electric thermostat heater drive
5V reference voltage
Comfort start input
Fault Description
Short circuit to ground
Short circuit to battery
Open circuit
Short circuit to ground
Short circuit to battery
Internal reference voltage error
Engine crank signal error (request
while engine running)
Serial link with immobilisation ECU Timed out
Serial link with immobilisation ECU Exchange code in EEPROM failure
Serial link with immobilisation ECU EEPROM read/write failure
ECM, throttle monitoring/ self test
Engine torque monitoring problem
ECM, throttle monitoring/ self test
Throttle position control deviation
Throttle drive
Motor power stage fault
ECM, throttle monitoring/ self test
'Limp home' position not adapted
ECM, throttle monitoring/ self test
Throttle position control band stuck
short
ECM, throttle monitoring/ self test
Throttle position control band stuck
long
ECM, throttle monitoring/ self test
Control gain adaption error
ECM, throttle monitoring/ self test
Throttle control range not learned
ECM, throttle monitoring/ self test
Throttle motor spring test failed
CAN bus link with ABS ECU
Timed out
CAN bus link with EAT ECU
Timed out
CAN bus link with instrument pack
Timed out
CAN bus link with transfer box ECU Timed out
ECM self test
Torque monitor error
ECM self test
Limp home monitor error
Serial link with immobilisation ECU Message parity bit fault (wrong
code)
Serial link with immobilisation ECU Exchange code implausible
Serial link with immobilisation ECU No start code programmed
Serial link with immobilisation ECU Message fault
Serial link with immobilisation ECU False manipulation of start code by
tester interface
Serial link with immobilisation ECU Start code corrupted
Transfer box ECU
Implausible signal
CAN bus link with transfer box ECU Message information error
BOSCH ME 7.2 ENGINE MANAGEMENT
Drive Cycles
TestBook/T4 drive cycles are as follows:
Drive cycle A
7 Switch on the ignition for 30 seconds.
8 Ensure engine coolant temperature is less than 60 °C (140 °F).
9 Start the engine and allow to idle for 2 minutes.
10 Connect TestBook/T4 and check for fault codes.
Drive cycle B
11 Switch ignition on for 30 seconds.
12 Ensure engine coolant temperature is less than 60 °C (140 °F).
13 Start the engine and allow to idle for 2 minutes.
14 Perform 2 light accelerations, i.e. 0 to 35 mph (56 km/h) with light pedal pressure.
15 Perform 2 medium accelerations, i.e. 0 to 45 mph (72 km/h) with moderate pedal pressure.
16 Perform 2 hard accelerations, i.e. 0 to 55 mph (88 km/h) with heavy pedal pressure.
17 Allow engine to idle for 2 minutes.
18 Connect TestBook/T4 and, with the engine still running, check for fault codes.
Drive cycle C
19 Switch ignition on for 30 seconds.
20 Ensure engine coolant temperature is less than 60 °C (140 °F).
21 Start the engine and allow to idle for 2 minutes.
22 Perform 2 light accelerations, i.e. 0 to 35 mph (56 km/h) with light pedal pressure.
23 Perform 2 medium accelerations, i.e. 0 to 45 mph (72 km/h) with moderate pedal pressure.
24 Perform 2 hard accelerations, i.e. 0 to 55 mph (88 km/h) with heavy pedal pressure.
25 Cruise at 60 mph (96 km/h) for 8 minutes.
26 Cruise at 50 mph (80 km/h) for 3 minutes.
27 Allow engine to idle for 3 minutes.
28 Connect TestBook/T4 and, with the engine still running, check for fault codes.
TestBook/T4 Diagnostics
207
BOSCH ME 7.2 ENGINE MANAGEMENT
The following areas have an associated readiness test which must be flagged as complete,
before a problem resolution can be verified:
•
•
•
•
Catalytic converter fault.
Evaporative loss system fault.
HO2S fault.
HO2S heater fault.
When carrying out drive cycle C to determine a fault in any of the above areas, select the
readiness test icon to verify that the test has been flagged as complete.
Drive cycle D
29 Switch ignition on for 30 seconds.
30 Ensure engine coolant temperature is less than 35 °C (95 °F).
31 Start the engine and allow to idle for 2 minutes.
32 Perform 2 light accelerations, i.e. 0 to 35 mph (56 km/h) with light pedal pressure.
33 Perform 2 medium accelerations, i.e. 0 to 45 mph (72 km/h) with moderate pedal pressure.
34 Perform 2 hard accelerations, i.e. 0 to 55 mph (88 km/h) with heavy pedal pressure.
35 Cruise at 60 mph (96 km/h) for 5 minutes.
36 Cruise at 50 mph (80 km/h) for 5 minutes.
37 Cruise at 35 mph (56 km/h) for 5 minutes.
38 Allow engine to idle for 2 minutes.
39 Connect TestBook/T4 and check for fault codes.
Drive cycle E
40 Ensure fuel tank is at least a quarter full.
41 Carry out drive cycle A.
42 Switch off ignition.
43 Leave vehicle undisturbed for 20 minutes.
44 Switch on ignition.
45 Connect TestBook/T4 and check for fault codes.
208
BOSCH ME 7.2 ENGINE MANAGEMENT
VCC System
Variable Camshaft Control Components
1
Locking nut
7
Oil distribution flange gasket
2
Impulse wheel
8
Inlet camshaft
3
Camshaft to sprocket retaining screw
4
VCC transmission unit
10
9
Drive train gear retaining bolt
Exhaust camshaft
5
Bolt
11
Check valve
6
Oil distribution flange
12
VCC solenoid valve
Introduction
The variable intake valve timing system is known as Variable Camshaft Control (VCC).
The VCC system is a new system providing stepless VCC functionality on each intake
camshaft. The system is continuously variable within its range of adjustment providing
optimized camshaft positioning for all engine operating conditions.
While the engine is running, both intake camshafts are continuously adjusted to their optimum
positions. This enhances engine performance and reduces exhaust emissions.
VCC System
209
BOSCH ME 7.2 ENGINE MANAGEMENT
Both camshafts are adjusted simultaneously within 20° (maximum) of the camshafts rotational
axis.
20
20
1
1
2
2
VCC transmission unit
2
M18 0818
1
VCC control solenoid valve
This equates to a maximum span of 40° crankshaft rotation. The camshaft spread angles for
both banks are as follows.
210
BOSCH ME 7.2 ENGINE MANAGEMENT
E
F
H
G
A
C
D
B
M18 0826
A
Valve lift
E
Default retard
B
Crankshaft rotation
F
Maximum retard
C
Open duration 228°
G
Exhaust valve
D
Open duration 236°
H
Intake valve
The design of a camshaft for a non adjustable valve timing system is limited to the required
overall performance of the engine.
An intake camshaft with an advanced (early) profile will provide a higher performing power
curve at a lower engine speed. But at idle speed the advanced position will create a large area
of intake/exhaust overlap that causes a rough, unstable idle.
An intake camshaft with a retarded (late) profile will provide a very smooth, stable idle but will
lack the cylinder filling dynamics needed for performance characteristics at mid range engine
speeds.
The ability to adjust the valve timing improves the engines power dynamics and reduces
exhaust emissions by optimizing the camshaft angle for all ranges of engine operation. VCC
provides the following benefits:
• Increased torque at lower to mid range engine speeds without a loss of power in the upper
range engine speeds
• Increased fuel economy due to optimized valve timing angles
• Reduction of exhaust emissions due to optimized valve overlap
• Smoother idle quality due to optimized valve overlap.
VCC System
211
BOSCH ME 7.2 ENGINE MANAGEMENT
Variable Camshaft Control Electronic Control
The following describes the electronic control of the VCC system.
Electronic Control
The engine control module is responsible for activating a VCC variable position solenoid valve
based on EMS program mapping. The activation parameters are influenced by the following
input signals:
•
•
•
•
Engine speed
Load (intake air mass)
Engine temperature
Camshaft position.
Mechanical Control
The position of the solenoid valve directs the hydraulic flow of engine oil. The controlled oil flow
acts on the mechanical components of VCC system to position the camshaft.
The hydraulic engine oil flow is directed through advance or retard activation oil ports by the
VCC solenoid. Each port exits into a sealed chamber on the opposite sides of a control piston.
In its default position the oil flow is directed to the rear surface of the piston. This pulls the
helical gear forward and maintains the retarded valve timing position.
When the oil flow is directed to the front surface of the piston, the oil pushes the helical gear in
the opposite direction which rotates the matched helical gearing connected to the camshaft.
The angled teeth of the helical gears cause the pushing movement to be converted into a
rotational movement. The rotational movement is added to the turning of the camshaft providing
the variable camshaft positioning.
System Components
The VCC components include the following for each cylinder bank:
•
•
•
•
•
•
Cylinder heads with oil ports for VCC
VCC transmission with sprockets
Oil distribution flange
Oil check valve
PWM controlled solenoid valve
Camshaft position impulse wheel.
212
BOSCH ME 7.2 ENGINE MANAGEMENT
Control Solenoid and Check Valve
A
B
C
M18 0812
A
Advance
B
Retard
C
Vent
The VCC solenoid is a two wire, pulse width modulated, oil pressure control valve. The valve
has four ports;
A check valve is positioned forward of the solenoid in the cylinder head oil gallery. The check
valve maintains an oil supply in the VCC transmission and oil circuits after the engine is turned
off. This prevents the possibility of piston movement (noise) within the VCC transmission
system on the next engine start.
VCC Transmission
The primary and secondary timing chain sprockets are integrated with the VCC transmission.
The transmission is a self contained unit.
The adjustment of the camshaft occurs inside the transmission, controlled oil pressure then
moves the piston axially.
The helical gear cut of the piston acts on the helical gears on the inside surface of the
transmission and rotates the camshaft to the specific advanced or retarded angle position.
Three electrical pin contacts are located on the front surface to verify the default maximum
retard position using an ohmmeter. This is required during assembly and adjustment. (see
service notes further on).
Oil Distribution Flanges:
The oil distribution flanges are bolted to the front surface of each cylinder head. They provide a
mounting location for the VCC solenoids as well as the advance-retard oil ports from the
solenoids to the intake camshafts.
VCC System
213
BOSCH ME 7.2 ENGINE MANAGEMENT
Camshafts
Each intake camshaft has two oil ports separated by three sealing rings on their forward ends.
The ports direct pressurized oil from the oil distribution flange to the inner workings of the VCC
transmission.
Each camshaft has REVERSE threaded bores in their centres for the attachment of the timing
chain sprockets on the exhaust cams and the VCC transmissions for each intake camshaft as
shown.
Camshaft Position Impulse Wheels:
The camshaft position impulse wheels provide camshaft position status to the engine control
module via the camshaft position sensors. The asymmetrical placement of the sensor wheel
pulse plates provides the engine control module with cylinder specific position ID in conjunction
with crankshaft position.
VCC Control
As the engine camshafts are rotated by the primary and secondary timing chains, the ECM
activates the VCC solenoids via a PWM (pulse width modulated) ground signal based on a
program map. The program is influenced by engine speed, load, and engine temperature.
In its inactive or default position, the valves direct 100% engine oil pressure flow to achieve
maximum “retard” VCC positioning
214
BOSCH ME 7.2 ENGINE MANAGEMENT
Maximum Retard Position
M18 0811
As the Pulse Width Modulation (PWM) increases on the control signal, the valve progressively
opens the advance oil port and proportionately closes the retarded oil port.
Mid Position
M18 0832
Oil pressure pushes the piston toward the advance position. Simultaneously the oil pressure on
the retarded side (rear) of the piston is decreased and directed to the vent port in the solenoid
valve and drains into the cylinder head.
At maximum PWM control, 100% oil flow is directed to the front surface of the piston pushing it
rearward to maximum advance.
VCC System
215
BOSCH ME 7.2 ENGINE MANAGEMENT
Maximum Advance Position
M18 0833
Varying the pulse width (on time) of the solenoids control signals proportionately regulates the
oil pressures on each side of the pistons to achieve the desired VCC advance angle.
VCC Timing Procedures
Always refer to RAVE for complete Valve Timing Procedures. The valve timing adjustment
requires the setting of the VCC transmissions to their maximum retard positions with an
ohmmeter and attaching the camshaft gears to each camshaft with single reverse threaded
bolts.
The process is as follows:
1 After locking the crankshaft at TDC, the camshaft alignment tools are placed on the square
blocks on the rear of the camshafts locking them in place
2 The exhaust camshaft sprockets and VCC transmission units with timing chains are placed
onto their respective camshafts
3 The exhaust camshaft sprockets and VCC transmissions are secured to the camshafts with
their respective single, reverse threaded bolt. Finger tighten only at this point. Install the
chain tensioner into the timing chain case and tension the chain
4 Connect an ohmmeter across two of the three pin contacts on the front edge of one of the
VCC transmissions. Twist the inner hub of transmission to the left (counter clock- size).
Make sure the ohmmeter indicates closed circuit. This verifies that the transmission is in
216
BOSCH ME 7.2 ENGINE MANAGEMENT
the default maximum retard position
5 Using an open end wrench on the camshaft to hold it in place, torque the VCC transmission
centre bolt to specification.
Camshaft Impulse Wheel Position Tools
The camshaft impulse wheels require a special tool set to position them correctly prior to
tightening the retaining nuts.
The impulse wheels are identical for each cylinder bank. The alignment hole in each wheel
must align with the tools alignment pin. Therefore the tools are different and must be used
specifically for their bank.
The tool rests on the upper edge of the cylinder head and is held in place by the timing case
bolts.
Refer to the relevant RAVE section for complete information.
VCC Solenoid Replacement
Refer to the appropriate RAVE section for complete solenoid replacement procedure.
The solenoids are threaded into the oil distribution flanges through a small opening in the upper
timing case covers.
VCC Transmission Retard Position Set Up Tools
A special tool (see RAVE for correct tool number) is used to rotate the transmission to the full
retard position when checking the piston position with an ohmmeter. This tool engages the inner
hub of the transmission provides an easy method of twisting it to the left for the ohmmeter test.
Diagnostics
The VCC is fully compatible with the diagnostic software providing specific fault codes and test
modules. Additionally, diagnostic requests section provides status of the PWM of the VCC
solenoids and camshaft position feedback via the camshaft position sensors. The Service
Functions section of the TestBook/T4 also provides a VCC system test.
VCC System
217
BOSCH ME 7.2 ENGINE MANAGEMENT
218
BOSCH ME 7.2 ENGINE MANAGEMENT
Connector Pinouts
ME7.2 ECU Pin Out Tables
Connector 1
Connector C0603
Pin
Wire
Number Color
Circuit Description
Circuit Status
1-01
1-02
1-03
1-04
N
Ground
1-05
N
Injector ground
1-06
N
Ground
1-07
R
Permanent battery supply
1-08
RU
Switched battery supply (via main
relay)
1-09
Connector Pinouts
219
BOSCH ME 7.2 ENGINE MANAGEMENT
Connector 2
Connector C0604
Pin
Number
Wire
Color
Circuit Description
Circuit Status
2-01
NW
Rear HO2S heater drive 2
12 – 0V Switching
2-03
YN
CAN ‘low’ signal
2-04
YB
CAN ‘high’ signal
2-07
NU
Rear HO2S heater drive 1
12 – 0V Switching
2-08
YW
Rear HO2S signal ground 2
0V
2-09
Y
Front HO2S signal ground 1
0V
2-10
YR
Front HO2S signal ground 2
0V
2-11
YU
Rear HO2S signal ground 1
0V
2-13
NR
Front HO2S heater drive 2
12 – 0V Switching
2-14
BW
Rear HO2S signal 2
.2 - .8V Steady *
2-15
B
Front HO2S signal 1
.2 - .8V Switching *
2-16
BR
Front HO2S signal 2
.2 - .8V Switching *
2-17
BU
Rear HO2S signal 1
.2 - .8V Steady *
N
Front HO2S heater drive 1
12 – 0V Switching
N
Main power relay drive (EMS main relay)
2-02
2-05
2-06
2-12
2-18
2-19
2-20
2-21
2-22
2-23
2-24
* Note: The signal circuits are held at .5V by ECM when the HO2S's are not switching.
220
BOSCH ME 7.2 ENGINE MANAGEMENT
Connector 3
Connector C0606
Pin
Number
Wire
Color
Circuit Description
Circuit Status
3-01
NY
Cylinder 2 (Injector 8)
3-02
NG
Cylinder 3 (Injector 6)
3-03
N
Purge valve drive
3-06
N
Ground
3-07
RG
5V reference supply to HFM
3-08
NR
Throttle position signal input 2
3-09
B
Air flow meter signal ground
3-10
N
Throttle sensor reference voltage supply
3-12
BG
Starter motor feedback
12V Cranking
3-13
U
Generator charge signal
Batt + Charging
3-14
NR
Cylinder 7 (Injector 7)
3-15
NS
Cylinder 6 (Injector 5)
3-16
GS
VCC drive 2
12 – 0V Switching
3-19
W
Camshaft sensor input signal 2
12 – 0V Switching
3-20
Y
Camshaft sensor input signal 1
12 – 0V Switching
3-21
NO
Water temperature signal ground
3-22
YG
Water temperature signal input
3-23
Y
Air flow meter signal input
3-24
P
Throttle position signal input 1
3-25
U
Throttle position signal ground
3-04
3-05
4.5 - .5V Closed – WOT
3-11
3-17
3-18
Connector Pinouts
.5 – 4.5 Closed - WOT
221
BOSCH ME 7.2 ENGINE MANAGEMENT
Pin
Number
Wire
Color
Circuit Description
3-27
NP
Cylinder 8 (Injector 4)
3-28
O
Cylinder 5 (Injector 2)
3-29
GU
VCC drive 1
3-31
NW
Electrically controlled thermostat drive
3-32
Y
Crankshaft sensor signal input A
Circuit Status
3-26
12 – 0V Switching
3-30
3-33
Electronic ground
3-34
YU
Air temperature signal input (from HFM)
3-35
N
Knock sensor ground (cylinders 3 & 4)
3-36
B
Knock sensor signal (cylinders 3 & 4)
3-37
B
Knock sensor signal (cylinders 7 & 8)
3-38
N
Knock sensor ground (cylinders 7 & 8)
3-40
NU
Cylinder 4 (Injector 3)
3-41
NW
Cylinder 1 (Injector 1)
3-42
W
Throttle position actuator 1
12 – 0V PWM @ 2K Hz
3-43
R
Throttle position actuator 2
12V
3-45
N
Crankshaft sensor signal ground
3-46
B
Crankshaft sensor signal input B
3-48
N
Knock sensor ground (cylinders 1 & 2)
3-49
B
Knock sensor signal (cylinders 1 & 2)
3-50
B
Knock sensor signal (cylinders 5 & 6)
3-51
N
Knock sensor ground (cylinders 5 & 6)
3-52
UY
Secondary air valve solenoid drive
3-39
3-44
3-47
222
BOSCH ME 7.2 ENGINE MANAGEMENT
Connector 4
Connector C0331
Pin
Number
Wire
Color
Circuit Description
4-01
U
Instrument pack generator warning
lamp
4-02
BG
Instrument pack engine cranking
signal
4-03
NU
Secondary air pump relay drive
4-04
BG
Condensor fan drive (via power
control ECU)
4-06
BY
Ignition switch crank position input
4-07
NG
Pedal position sensor 1 signal
ground
4-08
W
Pedal position sensor 1 signal input
4-09
Y
Pedal position sensor 1 reference
supply
4-10
BP
Fuel pump relay drive
4-12
UG
Pedal position sensor 2 signal
ground
4-13
WG
Pedal position sensor 2 signal input
4-14
YG
Pedal position sensor 2 reference
supply
Circuit Status
4-05
4-11
4-15
Ground
4-16
4-17
B
Engine speed signal output (to
diagnostic connector)
4-18
S
DM-TL heater drive
4-19
SP
Instrument pack
Connector Pinouts
0 –12V Pulse, engine running
223
BOSCH ME 7.2 ENGINE MANAGEMENT
Pin
Number
Wire
Color
Circuit Description
4-20
BG
DM-TL motor drive
4-21
SN
Light Control Module
4-22
YG
Vehicle speed signal input
UR
Brake pedal sensor input
4-26
GB
Ignition switch position 2 input
4-27
YB
Steering wheel switches input
(cruise switch input)
4-28
NS
Brake pedal sensor input
4-29
BG
Air con compressor disengage
output (to ATC ECU)
4-30
NU
DM-TL changeover valve drive
4-32
WPY
K-Diagnostic Line
4-33
BP
Immobilisation signal
4-36
YB
CAN ‘high’ signal
4-37
YN
CAN ‘low’ signal
4-38
US
Thermostat monitoring coolant
temperature sensor ground
4-39
BS
Thermostat monitoring coolant
temperature sensor signal
4-40
YN
Starter motor relay drive
Circuit Status
4-23
4-24
11V with pedal pressed
4-25
12V with pedal pressed
4-31
4-34
4-35
224
Batt + when cranking
BOSCH ME 7.2 ENGINE MANAGEMENT
Connector 5
Connector C0332
Pin
Number
Wire
Color
Circuit Description
5-01
BY
Ignition coil 7 (Cylinder 7)
5-02
BU
Ignition coil 8 (Cylinder 4)
5-03
BR
Ignition coil 2 (Cylinder 8)
5-04
BY
Ignition coil 3 (Cylinder 6)
5-05
N
Ignition ground
5-06
BW
Ignition coil 1 (Cylinder 1)
5-07
BU
Ignition coil 4 (Cylinder 3)
5-08
BW
Ignition coil 5 (Cylinder 2)
5-09
BR
Ignition coil 6 (Cylinder 5)
Connector Pinouts
Circuit Status
225
BOSCH ME 7.2 ENGINE MANAGEMENT
226
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
System Description
The KV6 engine is fitted with a Siemens MS43 Engine Management System (EMS), which is an
adaptive system that maintains engine performance at the optimum level throughout the life of
the engine.
The EMS consists of an Engine Control Module (ECM) that uses inputs from engine sensors
and from other vehicle systems to continuously monitor driver demand and the current status of
the engine. From the inputs the ECM calculates the Air Fuel Ratio (AFR) and ignition timing
required to match engine operation with driver demand, then outputs the necessary control
signals to the electric throttle, fuel injectors and ignition coils. The ECM also outputs control
signals to operate the:
• Air Conditioning (A/C) compressor.
• Engine cooling fans.
• Evaporative emissions (EVAP) purge valve and Diagnostic Module for Tank Leakage
(DMTL).
• Fuel pump.
• Variable Intake System (VIS).
The ECM also interfaces with the:
• Immobilization ECU, for re-mobilization of the engine fuel supply.
• Cruise control interface ECU, to operate cruise control.
• Electronic Automatic Transmission (EAT) ECU, to assist with control of the gearbox.
SIEMENS MS43 Engine Management System
227
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Engine Management System Component Location
1
Accelerator Pedal Position
sensor
11
Crankshaft Position sensor
2
A/C compressor clutch relay
12
Engine Coolant Temperature
sensor
3
Main relay
13
LH bank ignition coil (x 3)
4
Fuel pump relay
14
Fuel injector (x 6)
5
ECM
15
Knock sensors
6
Electric throttle
16
RH bank ignition coil (x 3)
7
Intake Air Temperature sensor
17
Malfunction Indicator Lamp
(emissions faults)
8
Mass Air Flow sensor
18
Service Engine lamp (nonemissions faults)
Camshaft Position sensor
19
Upstream HO2S (x 2)
Thermostat monitoring sensor
20
Downstream HO2S (x 2)
9
10
228
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Sensor inputs and engine performance are monitored by the ECM, which illuminates the
SERVICE ENGINE SOON (MIL) and/or the SERVICE ENGINE warning lamps in the instrument
pack if a fault is detected.
As part of the security system's immobilization function, a vehicle specific security code is
programmed into the ECM and the immobilization ECU during production. The ECM cannot
function unless it is connected to an immobilization ECU with the same code. In service,
replacement ECM are supplied uncoded and must be programmed using TestBook/T4 to learn
the vehicle security code from the immobilization ECU.
A 'flash' Electronic Erasable Programmable Read Only Memory (EEPROM) allows the ECM to
be externally configured, using TestBook/T4, with market specific or new information.
The ECM memorizes the position of the crankshaft and the camshaft when the engine stops.
During cranking on the subsequent start the ECM confirms their positions from sensor inputs
before initiating fuel injection and ignition.
To achieve optimum performance the ECM is able to 'learn' the individual characteristics of an
engine and adjust the fuelling calculations to suit. This capability is known as adaptive fuelling.
Adaptive fuelling also allows the ECM to compensate for wear in engine components and to
compensate for the tolerance variations of the engine sensors.
If the ECM suffers an internal failure, such as a breakdown of the processor or driver circuits,
there is no back up system or limp home capability. If a sensor circuit fails to supply an input,
where possible the ECM adopts a substitute or default value, which enables the engine to
function, although with reduced performance in some cases.
Engine Starting
When the ignition switch is in position II a power feed is connected from the ignition switch to
the ECM. The ECM then initiates 'wake up' routines and energizes the main and fuel pump
relays.
When the engine cranks, provided a valid mobilization signal is received from the
immobilization ECU, the ECM initiates throttle control, fuelling and ignition to start and maintain
control of the engine as necessary to meet driver demand. If no mobilization code is received
from the immobilization ECU, or the code is invalid, the ECM inhibits fuel injection and ignition
to prevent the engine from starting.
The electrical circuit from the fuel pump relay to the fuel pump is routed through the fuel cut-off
inertia switch, located below the E-box in the engine compartment. In the event of a collision the
switch breaks the circuit to prevent further fuel being delivered to the engine. The switch is reset
by pressing down the centre of the rubber cover on the top of the switch.
During the start sequence, the ECM also illuminates the MIL, as a bulb check. While the ignition
switch is in position II the MIL is continuously illuminated. The MIL is extinguished when the
ignition switch turns to position III and the engine starts.
System Description
229
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Engine Stopping
When the ignition switch is turned to position I, the ECM switches off the ignition coils, injectors
and fuel pump to stop the engine. The ECM continues to energize the main relay until the power
down functions are completed. Power down functions include the fuel tank leak check (6
minutes maximum), engine cooling (5 minutes maximum) and memorising data for the next
start up. If neither a fuel tank lank check nor engine cooling are required, the power down
process takes approximately 10 seconds.
When the power down process is completed, the ECM de-energizes the main relay and enters
a low power mode. In the low power mode, maximum quiescent drain is 0.5 mA.
ECM
The ECM is located in the engine compartment, in the E-box. Five connectors provide the
interface between the ECM and the vehicle wiring.
Controller Area Network (CAN) Bus
The ECM is connected to the Anti-lock Braking System (ABS) modulator, EAT ECU and the
instrument pack by the CAN bus.
Electric Throttle
The electric throttle controls the air flow into the engine. In addition to the normal engine power
control function, the electric throttle allows the cruise control, idle speed control and engine
speed limiting functions to be performed without the need for additional hardware.
The electric throttle consists of a throttle body which incorporates a throttle plate driven by a DC
motor via reduction gears. A return spring biases the throttle plate in the closed direction.
Operation of the DC motor is controlled by the ECM, which outputs two Pulse Width Modulated
(PWM) signals to a direction controlled H bridge drive in the motor. To enable closed loop
control, the position of the throttle plate is supplied to the ECM by two feedback potentiometers
in the throttle body.
230
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
The feedback potentiometers have a common 5 volt supply and a common ground connection
from the ECM, and produce separate linear signal voltages to the ECM proportional to the
position of the throttle plate. The ECM uses the signal from feedback potentiometer 1 as the
primary signal of throttle plate position, and the signal from feedback potentiometer 2 for
plausibility checks.
• The signal from feedback potentiometer 1 varies between 0.5 volt (0% throttle open) and
4.5 volts (100% throttle open)
• The signal from feedback potentiometer 2 varies between 4.5 volts (0% throttle open) and
0.5 volt (100% throttle open)
1
DC motor
3
Reduction gear/ feedback potentiometer housing
2
Electrical connector
4
Throttle plate
While the ignition is on, the ECM continuously monitors the two feedback potentiometers for
short and open circuits and checks the feedback potentiometer signals, against each other and
the inputs from the Accelerator Pedal Position (APP) sensor, for plausibility. If a fault is detected
in the feedback potentiometer signals or the DC motor, the ECM:
• Stores a related fault code in memory.
• Illuminates the SERVICE ENGINE warning lamp in the instrument pack.
• Adopts a throttle limp home mode or disables throttle control, depending on the nature of
the fault.
Electric Throttle
231
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
In the throttle limp home mode the ECM uses the throttle plate to regulate engine speed at 1400
rev/min while the brake pedal is released and idle speed while the brake pedal is pressed. If the
ECM disables throttle control, the DC motor is de-energized and the return spring holds the
throttle valve closed; the ECM attempts to keep the engine running at idle speed using the
ignition timing and fuelling, although the engine is likely to run rough or stall, depending on
engine temperature and ambient conditions.
If a plausibility fault between the feedback potentiometer signals is detected, the ECM
calculates a virtual throttle plate position from engine mass air flow and compares this to the
feedback potentiometer signals:
• If one of the feedback potentiometer signals matches the virtual throttle position, the ECM
adopts the limp home mode and uses the valid signal to monitor throttle plate position. To
ensure safe operation, the ECM continues to use the virtual throttle plate position for plausibility checks with the valid signal.
• If neither of the feedback potentiometer signals is plausible, the ECM disables throttle control.
Engine Sensors
The EMS incorporates the following engine sensors:
•
•
•
•
•
•
•
•
•
An Accelerator Pedal Position (APP) sensor.
A Crankshaft Position (CKP) sensor.
A Camshaft Position (CMP) sensor.
A Mass Air Flow (MAF) sensor.
An Intake Air Temperature (IAT) sensor.
An Engine Coolant Temperature (ECT) sensor.
A thermostat monitoring sensor.
Four Heated Oxygen Sensors (HO2S).
Two knock sensors.
232
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Accelerator Pedal Position (APP) Sensor
The APP sensor enables the ECM to determine the throttle position requested by the driver on
the accelerator pedal.
The APP sensor is installed on the pedal box and consists of a twin track potentiometer with
wipers driven by a linkage connected to the accelerator pedal. Each potentiometer track has a 5
volt supply and ground connection from the ECM, and produces a linear signal voltage to the
ECM proportional to the position of the accelerator pedal. The signal voltage from track 1 of the
potentiometer is approximately double that of the signal voltage from track 2.
From the sensor signals, the ECM determines driver demand as a percentage of pedal travel,
where 0% is with the pedal released and 100% is with the pedal fully depressed. Driver demand
is then used to calculate throttle angle, fuel quantity and ignition timing. The ECM also outputs
driver demand on the CAN system, for use by the brake and gearbox control systems.
The ECM stores the signal values that correspond with closed and wide open throttle, and
adapts to new values to accommodate component wear or replacement.
The signals from the APP sensor are monitored by the ECM for short and open circuits and
plausibility. If a fault is detected, the ECM:
• Stores a related fault code in memory.
• Illuminates the SERVICE ENGINE warning lamp in the instrument pack.
• Inhibits the driver demand message on the CAN bus, which disables the Hill Descent Control (HDC) function of the ABS modulator and reduces the performance of the automatic
gearbox (harsh gear changes and loss of kickdown).
• Adopts a sensor limp home mode or the throttle limp home mode (see Electric Throttle,
Engine Sensors
233
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
above), depending on the nature of the fault.
The ECM adopts the sensor limp home mode if a plausibility fault between the two sensor
signals is detected. In the sensor limp home mode, the ECM:
• Uses the signal with the lowest throttle demand, which causes a slower throttle response
and reduces the maximum throttle position.
• Sets the throttle plate and fuelling to idle when the brake pedal is pressed.
Crankshaft Position Sensor (CKP)
The CKP sensor provides the ECM with a digital signal of the rotational speed and angular
position of the crankshaft, for use in ignition timing, fuel injection timing and fuel injection
quantity calculations. To determine the exact position of the crankshaft in the engine cycle, the
ECM must also use the input from the CMP sensor.
The CKP sensor is mounted on the front of the gearbox housing, in line with the outer
circumference of the torque converter. The sensing tip of the CKP sensor is adjacent to a
reluctor ring formed in the periphery of the torque converter. The reluctor ring has 58 teeth
spaced at 6° intervals. A gap equivalent to two missing teeth, 36° After Top Dead Centre
(ATDC) of No. 1 cylinder, provides the ECM with a reference point.
The CKP sensor operates using the Hall effect principle. A permanent magnet inside the sensor
applies a magnetic flux to a semiconductor, which receives a power supply from the main relay.
The output voltage from the semiconductor is fed to the ECM. As the gaps between the poles of
the reluctor ring pass the sensor tip the magnetic flux is interrupted, causing a fluctuation of the
output voltage and producing a digital signal.
If the CKP sensor fails the ECM immediately stops the engine.
234
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Camshaft Position Sensor (CMP)
M19 2837A
The CMP sensor provides a signal which enables the ECM to determine the position of the
camshaft relative to the crankshaft. This allows the ECM to synchronize fuel injection for start
and run conditions.
The CMP sensor is located on the camshaft cover of the LH (front) cylinder bank, at the
opposite end to the camshaft drive, in line with a 'half moon' reluctor on the exhaust camshaft.
The reluctor is a single tooth which extends around 180° of the camshaft circumference.
The CMP sensor operates using the Hall effect principle. A permanent magnet inside the
sensor applies a magnetic flux to a semiconductor, which receives a power supply from the
main relay. The output voltage from the semiconductor is fed to the ECM. As the gap in the
reluctor passes the sensor tip, the magnetic flux is interrupted, causing a fluctuation of the
output voltage and producing a digital signal.
If the CMP sensor fails during engine running, the engine will run normally until turned off, but
will not restart until the CMP sensor input is restored.
Engine Sensors
235
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Mass Air Flow Sensor (MAF)
The MAF sensor provides a signal which the ECM uses for engine load calculations.
The MAF sensor is a hot film type, and is located in the intake system between the air filter
housing and the throttle body.
A closed-loop control circuit in the MAF sensor maintains a thick film resistor at a constant 200
°C (392 °F) above ambient temperature. The current required to maintain the temperature of
the thick film resistor, against the cooling effect of the air flowing through the sensor, provides a
precise, non-linear, measure of the air mass entering the engine.
The MAF sensor receives a battery voltage power supply and generates an output signal to the
ECM, between 0 and 5 volts, which is proportional to the air mass drawn into the engine.
In the event of a MAF sensor signal failure, the following symptoms may be apparent:
•
•
•
•
•
During driving engine speed may dip before recovering.
Difficult starting.
Engine stalls after starting.
Delayed throttle response.
Reduced engine performance.
236
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Intake Air Temperature Sensor (IAT)
1
Sensor
2
Housing
The IAT sensor provides a signal that enables the ECM to adjust ignition timing and fuelling
quantity according to the intake air temperature, thus ensuring optimum performance,
driveability and emissions.
The IAT sensor is a Negative Temperature Coefficient (NTC) thermistor located in a plastic
housing installed in the intake duct between the MAF sensor and the throttle body. The sensor
is a push fit in the housing and sealed by an 'O' ring. A clip is integrated into the sensor to
secure it in the housing.
If the input from the IAT sensor fails, the vehicle will continue to run. The ECM will substitute a
default value using the information from the speed/load map to run the engine, but adaptive
fuelling will be disabled.
Engine Coolant Temperature Sensor (ECT)
The ECT sensor provides the ECM with a signal voltage that varies with coolant temperature, to
enable the ECM to adapt the fuelling quantity and ignition timing with changes of engine
temperature.
Engine Sensors
237
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
The ECT sensor is located between the cylinder banks, between cylinders 3 and 6.
The ECT sensor consists of an encapsulated Negative Temperature Coefficient (NTC)
thermistor which is in contact with the engine coolant. As the coolant temperature increases the
resistance across the sensor decreases and as the coolant temperature decreases the sensor
resistance increases. To determine the coolant temperature, the ECM supplies the sensor with
a regulated 5 volts power supply and monitors the return signal voltage. The ECM also outputs
the coolant temperature on the CAN system, to operate the coolant temperature gauge.
If the ECT signal is missing, or outside the acceptable range, the ECM assumes a default
temperature reflecting a part warm engine condition. This enables the engine to function, but
with reduced driveability when cold and increased emissions, resulting from an over rich
mixture, when the engine reaches normal operating temperature. The ECM will also switch on
the cooling fans to prevent the engine and gearbox from overheating.
Thermostat Monitoring Sensor
The input from the thermostat monitoring sensor is used by the ECM to monitor the operation of
the cooling system thermostat and to control the operation of the engine cooling fans.
The thermostat monitoring sensor is a NTC thermistor installed in a plastic 'T' piece in the
radiator bottom hose. The sensor is a push fit in the T piece and sealed by an 'O' ring. A clip is
integrated into the sensor to secure it in the T piece.
238
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Heated Oxygen Sensor (HO2S)
1
Downstream HO2S
2
Upstream HO2S
The EMS has four HO2S:
• One upstream of each catalytic converter, identified as LH and RH front HO2S.
• One downstream of each catalytic converter, identified as LH and RH rear HO2S.
The LH and RH front HO2S enable the ECM to determine the AFR of the mixture being burned
in each cylinder bank of the engine. The LH and RH rear HO2S enable the ECM to monitor the
performance of the catalytic converters and the upstream oxygen sensors, and trim fuel.
Each HO2S consists of a sensing element with a protective ceramic coating on the outer
surface. The outer surface of the sensing element is exposed to the exhaust gas, and the inner
surface is exposed to ambient air. The difference in the oxygen content of the two gases
produces an electrical potential difference across the sensing element. With a rich mixture, the
low oxygen content in the exhaust gas results in a higher sensor voltage. With a lean mixture,
the high oxygen content in the exhaust gas results in a lower sensor voltage.
During closed loop control, the voltage of the two front HO2S switches from less than 0.3 volt to
more than 0.5 volt. The voltage switches between limits every two to three seconds. This
switching action indicates that the ECM is varying the AFR within the Lambda window
tolerance, to maximize the efficiency of the catalytic converters.
Engine Sensors
239
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Sectioned View of HO2S
1
V
A
2
3
B
M19 2959
A
Ambient air
B
Exhaust gases
1
Protective ceramic coating
2
Electrodes
3
Zirconium oxide
The material of the sensing element only becomes active at a temperature of approximately 300
°C (570 °F). To shorten the warm up time and minimize the emissions from a cold start and low
load conditions, each HO2S contains a heating element powered by a supply from the main
relay. The earth paths for the heating elements are controlled by the ECM. On start up, the
current supplied to the heating elements is increased gradually to prevent sudden heating from
damaging the ceramic coating. After the initial warm up period the ECM modulates the earth of
the heating elements, from a map of engine speed against mass air flow, to maintain the HO2S
at the optimum operating temperature.
The nominal resistance of the heating elements is 6 Ω at 20 °C (68 °F).
If an HO2S fails, the ECM illuminates the MIL. If a front HO2S fails the ECM also adopts open
loop fuelling and catalytic converter monitoring is disabled. If a rear HO2S fails, catalytic
converter and upstream HO2S monitoring is disabled.
240
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Knock Sensors
M19 2840
The knock sensors enable the ECM to operate the engine at the limits of ignition advance, for
optimum efficiency, without combustion knock damaging the engine. The ECM uses two knock
sensors, one for each cylinder bank, located between the cylinder banks on cylinders 3 and 4.
The knock sensors consist of piezo ceramic crystals that oscillate to create a voltage signal.
During combustion knock, the frequency of crystal oscillation increases, which alters the signal
output to the ECM. The ECM compares the signal to known signal profiles in its memory. If the
onset of combustion knock is detected the ECM retards the ignition timing for a number of
cycles. When the combustion knock stops, the ignition timing is gradually advanced to the
original setting.
The knock sensor leads are of different lengths to prevent incorrect installation.
Ignition Coils
1
RH bank ignition coil
2
LH bank ignition coil
The ECM uses a separate ignition coil for each spark plug. The ignition coils for the LH bank
spark plugs are positioned on the forward tracts of the Intake manifold and connected to the
spark plugs with High Tension (HT) leads. The ignition coils for the RH bank spark plugs are of
the plug top design, secured to the camshaft cover with 2 screws.
Ignition Coils
241
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Each ignition coil has 3 connections in addition to the spark plug connection; an ignition feed
from the main relay, an earth wire for the secondary winding and a primary winding negative
(switch) terminal. The switch terminal of each ignition coil is connected to a separate pin on the
ECM to allow independent switching. The ignition coils are charged whenever the ECM
supplies an earth path to the primary winding negative terminal. The duration of the charge time
is held relatively constant by the ECM for all engine speeds. Consequently, the dwell period
increases with engine speed. This type of system, referred to as Constant Energy, allows the
use of low impedance coils with faster charge times and higher outputs.
The ECM calculates the dwell period using inputs from the following:
• Battery voltage (main relay).
• CKP sensor.
• Ignition coil primary current (internal ECM connection).
The spark is produced when the ECM breaks the primary winding circuit. This causes the
magnetic flux around the primary winding to collapse, inducing HT energy in the secondary coil,
which can only pass to earth by bridging the air gap of the spark plug.
Ignition related faults are monitored indirectly by the misfire detection function.
Ignition Timing
The ECM calculates ignition timing using inputs from the following sensors:
•
•
•
•
•
CKP sensor.
MAF sensor.
Knock sensors.
TP sensor (idle only).
ECT sensor.
At start up and idle the ECM sets ignition timing by referencing the ECT and CKP sensors.
Once above idle the ignition timing is controlled according to maps stored in the ECM memory
and modified according to additional sensor inputs and any adaptive value stored in memory.
The maps keep the ignition timing within a narrow band that gives an acceptable compromize
between power output and emission control. The ignition timing advance and retard is
controlled by the ECM in order to avoid combustion knock.
Knock Control
The ECM uses active knock control to prevent combustion knock damaging the engine. If the
knock sensor inputs indicate the onset of combustion knock, the ECM retards the ignition timing
for that particular cylinder by 3°. If the combustion knock indication continues, the ECM further
retards the ignition timing, in decrements of 3°, for a maximum of 15° from where the onset of
combustion knock was first sensed. When the combustion knock indication stops, the ECM
restores the original ignition timing in increments of 0.75°.
To reduce the risk of combustion knock at high intake air temperatures, the ECM retards the
ignition timing if the intake air temperature exceeds 55 °C (169 °F). The amount of ignition
retard increases with increasing air intake temperature.
242
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Idle Speed Control
The ECM controls the engine idle speed using a combination of fuelling, ignition timing and the
electric throttle.
When the engine idle speed fluctuates the ECM initially varies the ignition timing, which
produces rapid changes of engine speed. If this fails to correct the idle speed, the ECM also
adjusts the electric throttle and fuelling.
Misfire Detection
The ECM uses the CKP sensor input to monitor the engine for misfires. As the combustion
charge in each cylinder is ignited the crankshaft accelerates, then subsequently decelerates. By
monitoring the acceleration/ deceleration pulses of the crankshaft the ECM can detect misfires.
Low fuel level:
When the fuel tank is almost empty there is a risk that air may be drawn into the fuel system,
due to fuel 'slosh', causing fuel starvation and misfires. To prevent false misfire faults being
logged, the ECM disables misfire detection if it receives a low fuel level message on the CAN
bus. Fuel tank content is monitored by the instrument pack, which transmits the low fuel level
message if the fuel tank content decreases to less than 15% (8.85 litres; 2.34 US galls).
Rough road disable:
When the vehicle is travelling over a rough road surface the engine crankshaft is subjected to
torsional vibrations caused by mechanical feedback from the road surface through the
transmission. To prevent misinterpretation of these torsional vibrations as a misfire, the misfire
monitor is disabled when a road surface exceeds a roughness limit programmed into the ECM.
The roughness of the road is calculated by the ABS modulator, from the four ABS sensor inputs,
and transmitted to the ECM on the CAN bus.
Fuel Injectors
M19 2845A
A split stream, air assisted fuel injector is installed for each cylinder. The injectors are located in
the Intake manifolds and connected to a common fuel rail assembly.
Each injector contains a pintle type needle valve and a solenoid winding. The needle valve is
held closed by a return spring. An integral nozzle shroud contains a ported disc, adjacent to the
nozzles. 'O' rings seal the injector in the fuel rail and the Intake manifold.
Fuel Injectors
243
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
The solenoid winding of each injector receives a 12 volt supply from the main relay. To inject
fuel, the ECM supplies an earth path to the solenoid winding, which energizes and opens the
needle valve. When the needle valve opens, the two nozzles direct a spray of atomized fuel
onto the back of each Intake valve. Air drawn through the shroud and ported disc improves
atomization and directional control of the fuel. The air is supplied from a dedicated port in the
intake duct via a plastic tube and tracts formed in the gasket face of the intake manifolds.
Each injector delivers fuel once per engine cycle, during the Intake stroke. The ECM calculates
the open time (duty cycle) of the injectors from:
•
•
•
•
Engine speed.
Mass air flow.
Engine temperature.
Accelerator pedal position (i.e. driver demand).
The fuel in the fuel rail is maintained at a pressure of 3.5 bar (51 lbf/in2) by a pressure regulator
incorporated into the pump unit in the fuel tank. An accumulator is attached to the fuel rail on the
RH Intake manifold to damp out pressure pulses from the pump and ensure that the pressure in
the fuel rail is constant (the same component functions as the pressure regulator on vehicles
with a return fuel delivery system). The accumulator is connected by a pipe to the Intake
manifold from which it receives a vacuum to aid the damping process. A Schraeder valve is
installed in the 'fuel return' pipe of the accumulator to allow pressure to be released from the
fuel rail and fuel feed pipe prior to maintenance.
The nominal resistance of the injector solenoid winding is 13 - 16 Ω at 20 °C (68 °F).
Evaporative Emissions (EVAP) Purge Valve
The ECM provides a PWM earth path to control the operation of the purge valve. When the
ECM is in the open loop fuelling mode the purge valve is kept closed. When the vehicle is
moving and in the closed loop fuelling mode the ECM opens the purge valve.
When the purge valve is open fuel vapour is drawn from the EVAP canister into the Intake
manifold. The ECM detects the resultant enrichment of the AFR, from the inputs of the front
HO2S, and compensates by reducing the duty cycle of the fuel injectors.
Variable Intake System (VIS) Valves
The ECM operates the two VIS valve motors to open and close the VIS valves in a
predetermined sequence based on engine speed and throttle opening. Each VIS valve motor
has a permanent power feed from the main relay, feedback and signal connections with the
ECM, and a permanent earth connection. When the engine starts, the VIS valve motors are
both in the valve open position. To close the VIS valves, the ECM applies a power feed to the
signal line of the applicable VIS valve motor. To open the VIS valves, the ECM disconnects the
power feed from the signal line and the VIS valve motor is closed by the power feed from the
main relay.
244
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Warning Lamps
Two warning lamps in the instrument are used to indicate faults with the engine management
system. The engine malfunction lamp consists of an amber SERVICE ENGINE legend and is
illuminated to indicate the detection of a non emissions related fault. The Malfunction Indicator
Lamp (MIL) consists of an amber SERVICE ENGINE SOON legend and is illuminated to
indicate the detection of an emissions related fault. The ECM operates the warning lamps, by
communicating with the instrument pack on the CAN bus. If a fault that can cause catalytic
converter damage is detected, the warning lamps flash. For other faults the warning lamps are
continuously illuminated.
Diagnostics
The ECM incorporates On Board Diagnostics (OBD) software that complies with market
legislation current at the time of manufacture. During engine operation the ECM performs self
test and diagnostic routines to monitor the performance of the engine and the EMS. If a fault is
detected the ECM stores a related diagnostic trouble code (also known as a 'P' code) in a non
volatile memory and, for most faults, illuminates the engine SERVICE ENGINE and/or the
SERVICE ENGINE SOON warning lamps. Codes are retrieved using TestBook/T4, which
communicates with the ECM via an ISO 9141 K line connection from the diagnostic socket.
Warning Lamps
245
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
246
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Siemens MS43 ECU Pin Out Tables
Connector C0603
Pin
Wire
Number Color
Circuit Description
1-01
W
Ignition sense
1-04
B
Electronic earth
1-05
B
Injector earth
1-06
B
Power stage earth
1-07
NG
Permanent battery supply
1-08
NK
Main relay power
1-09
NK
Main relay power
Circuit Status
1-02
1-03
Connector C0604
Pin
Wire
Number Color
Circuit Description
Circuit Status
2-01
UY
LH bank front HO2S heater drive
12 – 0V Switching
GY
LH bank rear HO2S heater drive
12 – 0V Switching
2-02
2-03
2-04
2-05
2-06
2-07
2-08
2-09
2-10
2-11
Siemens MS43 ECU Pin Out Tables
247
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Pin
Wire
Number Color
Circuit Description
Circuit Status
2-12
2-13
GY
RH bank front HO2S heater drive
12 – 0V Switching
2-14
UN
LH bank front HO2S signal
.2 - .8V Switching *
2-15
GN
RH bank front HO2S signal
.2 - .8V Switching *
2-16
UN
LH bank rear HO2S signal
.2 - .8V Switching *
2-18
GN
RH bank rear HO2S signal
.2 - .8V Switching*
2-19
UY
RH bank rear HO2S heater drive
12 – 0V Switching
2-20
BG
LH bank front HO2S earth
2-21
BG
RH bank front HO2S earth
2-22
BG
LH bank rear HO2S earth
2-23
NG
Main relay drive
2-24
BG
RH bank rear HO2S earth
2-17
Active low
* Note: The signal circuits are held at .5V by ECM when the HO2S's are not switching.
Connector C0606
Pin
Wire
Number Color
Circuit Description
Circuit Status
3-01
GW
MAF sensor signal
0 – 5V
BS
Brake vacuum enhancer solenoid
valve
Batt + in Gear
UG
CMP sensor signal
0 – 5V Square wave
3-07
NW
Throttle feedback potentiometer
supply
5V
3-08
WU
CKP sensor signal
0 – 5V Square wave
3-10
NU
Throttle feedback potentiometer 2
signal
5V @ Closed Throttle
3-11
SB
VIS balance motor drive
Active low
3-02
3-03
3-04
3-05
3-06
3-09
248
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Pin
Wire
Number Color
Circuit Description
Circuit Status
3-12
3-13
3-14
3-15
3-16
3-17
YW
MAF sensor earth
3-18
BS
CMP sensor earth
3-19
NP
Throttle feedback potentiometer 1
signal
3-20
NG
Throttle feedback potentiometer
earth
3-21
BS
CKP sensor earth
3-22
OG
IAT sensor signal
3-23
OS
IAT sensor earth
3-24
KB
ECT sensor signal
3-25
KG
ECT sensor earth
3-29
BO
LH bank knock sensor
3-30
BK
LH bank knock sensor
3-31
LGS
RH bank knock sensor
3-32
BK
RH bank knock sensor
3-33
Y
Fuel injector 1
3-34
YU
Fuel injector 3
3-35
YP
Fuel injector 5
3-36
YN
Fuel injector 2
3-37
YG
Fuel injector 6
3-38
YR
Fuel injector 4
0V 2 Closed Throttle
3-26
3-27
3-28
3-39
3-40
Siemens MS43 ECU Pin Out Tables
249
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Pin
Wire
Number Color
Circuit Description
Circuit Status
3-41
3-42
BO
EVAP purge valve drive
0 –12V PWM
3-43
NB
Throttle motor open drive
0 – 12V PWM
3-44
GW
Throttle motor closed drive
0 – 12V PWM
3-48
B
Knock sensors screen
3-49
BG
VIS power valves motor drive
BG
DMTL heater drive
3-45
3-46
3-47
Active low
3-50
3-51
3-52
Connector C0331
Pin
Wire
Number Color
Circuit Description
Circuit Status
UW
Engine cooling fan control
0 – 12V PWM
4-07
RU
APP sensor earth 2
4-08
YR
APP sensor signal 2
4-09
RN
APP sensor supply 2
4-10
BP
Fuel pump relay control
4-12
UR
APP sensor earth 1
4-13
RY
APP sensor signal 1
4-14
NR
APP sensor supply 1
4-01
4-02
4-03
4-04
4-05
4-06
.7 – 3.7V Closed – Open
throttle
4-11
250
.35 – 1.85V Closed – Open
throttle
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Pin
Wire
Number Color
Circuit Description
Circuit Status
4-15
4-16
4-17
4-18
4-19
4-20
GR
DMTL pump motor
4-21
GK
Alternator load sensing
4-22
WO
Vehicle speed
4-23
OB
VIS balance valve position
feedback
Active high
4-24
PG
Brake pedal sensor input
12V with pedal pressed
4-27
RG
Cruise control interface MFL signal
4-28
GR
Brake pedal sensor input
4-29
UB
Air con compressor clutch relay
4-30
U
DMTL solenoid valve drive
4-32
K
Diagnostic ISO 9141 K Line
4-33
YR
Immobilisation signal
4-34
UK
VIS power valves position feedback Active high
4-36
YB
CAN bus ‘high’ signal
4-37
YN
CAN bus ‘low’ signal
4-38
GU
Thermostat monitoring sensor earth
4-39
UG
Thermostat monitoring sensor
signal
0 – 12V PWM
4-25
4-26
12V with pedal pressed
4-31
0 – 12V Data
4-35
4-40
Siemens MS43 ECU Pin Out Tables
251
SIEMENS MS43 ENGINE MANAGEMENT SYSTEM
Connector C0332
Pin
Wire
Number Color
Circuit Description
5-01
BP
Ignition coil 5
5-02
BW
Ignition coil 3
5-03
BR
Ignition coil 1
5-05
B
Ignition earth
5-06
B
Ignition coil earth
5-07
BY
Ignition coil 4
5-08
BU
Ignition coil 6
5-09
BG
Ignition coil 2
5-04
252
Circuit Status
DENSO ENGINE MANAGEMENT
DENSO ENGINE MANAGEMENT
General
The V8 4.2 Liter supercharged engine is controlled by an ECM manufactured by DENSO. The
Engine Management System (EMS) controls the following:
•
•
•
•
•
•
•
•
•
Engine fueling
Ignition timing
Closed loop fueling
Knock control
Idle speed control
Emission control
OBD
Interface with the immobilization system
Speed control
The ECM controls the engine fueling by providing sequential fuel injection to all cylinders.
Ignition is controlled by a direct ignition system, provided by eight plug top coils. The ECM is
able to detect and correct for ignition knock on each cylinder and adjust the ignition timing for
each cylinder to achieve optimum performance.
The ECM uses a torque-based strategy to generate the torque required by the driver and other
vehicle control modules. The EMS uses various sensors to determine the torque required from
the engine. The EMS also interfaces with other vehicle electronic control modules's, via the
CAN bus, to obtain additional information (e.g. road speed from the ABS control module). The
EMS processes these signals and decides how much torque to generate. Torque is then
generated by using various actuators to supply air, fuel and spark to the engine (electronic
throttle, injectors, coils, etc.).
General
253
DENSO ENGINE MANAGEMENT
4.2 Liter Electronic Engine Controls
NOTE: Component Location (Sheet 1of 2)
254
1
PCV valve
7
MAPT sensor
13
CKP sensor
2
Fuel rail temperature sensor
8
CMP sensor
14
Spark plugs
3
Electric throttle
9
MAP sensor
15
Ignition coils
4
RFI capacitor
10
Universal Heated Exhaust Gas
Oxygen (UHEGO) sensors
16
MAF/IAT
5
Injectors
11
CMP sensor
6
Knock sensor
12
Heated Exhaust Gas Oxygen
(HEGO) sensors
DENSO ENGINE MANAGEMENT
4.2 Liter Electronic Engine Controls
NOTE: Component Location (Sheet 2 of 2)
1
Main relay
3
ECM
5
Brake light switch
2
Transfer box control module
4
APP
6
ABS control module
General
255
DENSO ENGINE MANAGEMENT
Engine Control Module (ECM)
The ECMis located in the E-Box in the plenum
area on the passenger side of the engine
compartment attached to the bulkhead.
System ECM has the following inputs:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
RCM
Park/neutral switch
Ignition coil feedback x2
Fuel rail temperature
Fuel rail pressure
Supercharger inlet pressure
Mass air flow
Engine speed
Camshaft position x2
Driver demand
Brake pedal position switch
Speed control switches
Generator load
Oxygen sensors pre catalyst x2
Oxygen sensors post catalyst x2
Throttle position
Cooling fan speed
Ignition switch position
Knock sensors x2
MAP
Intercooler temperature
Coolant temperature
Engine oil temperature
256
The ECM outputs to the following:
•
•
•
•
•
•
•
•
•
•
•
•
•
Throttle Actuator
Brake vacuum pump relay
Ignition coils (x8)
Oxygen sensor heaters (4)
Fuel injectors (8)
Purge Valve
Engine Cooling Fan
Fuel pump relay
Starter Relay
EMS Main Relay
Viscous Fan Control
Generator Control
Diagnostic Module Tank Leakage (DMTL)
(NAS Only)
• E box fan
• FPDM
DENSO ENGINE MANAGEMENT
4.2 Liter Electronic Engine Controls-Input Control Diagram (Sheet 1 of 2)
NOTE: Voltage sensor inputs
1
Main relay
8
Engine oil temperature sensor
15
Fuel rail pressure sensor
2
CMP sensor x2
9
MAF/IAT sensor
16
ECM
3
CKP sensor
10
Fuel rail temperature sensor
17
Fuse 27E
4
ECT sensor
11
RCM
18
Fuse 13E
5
APP sensor
12
Brake light switch
19
Ignition switch
6
MAPT sensor
13
Park/ neutral signal from TCM
20
Fuse 10E
7
MAP sensor
14
Knock sensors
Engine Control Module (ECM)
257
DENSO ENGINE MANAGEMENT
4.2 Liter Electronic Engine Controls-Control Diagram (Sheet 2 of 2)
NOTE: A= Hardwired D= CAN
258
1
Injectors
10
Adaptive speed control sensor
19
Generator
2
Engine cooling fan control/monitor
11
Adaptive speed control module
20
ECM
3
ABS control module
12
Transfer box control module
21
Fuel pump relay
4
Steering angle sensor
13
Electric park brake control module
22
FPDM
5
Terrain response control module
14
ATC control module
23
Speed control switches
6
Instrument cluster
15
DMTL pump
24
Clock spring
7
TCM
16
UHEGOs
25
Electric throttle
8
RCM
17
Ignition coils
9
Differential control module
18
HEGOs
DENSO ENGINE MANAGEMENT
Air Intake System
1
Air filter box
3
Air intake
2
Porous duct
4
Throttle body intake
5
Induction resonator chambers
The 4.2 Liter V8 SC engine air intake and distribution system comprises:
•
•
•
•
•
•
Air filter box
Air intake
Porus duct
Air filter and filter box
Intake duct
Electronic throttle.
Air Intake System
259
DENSO ENGINE MANAGEMENT
Air Filter Box
The air filter box is located in the front of the engine bay on the inside of the RH front wing. Air is
drawn from the air intake in the wing through a porous duct and into the air filter box. The filter
box contains a paper air filter element.
Air Intake Duct
The air intake duct runs from the throttle body to the air filter box. The duct comprises two
separate pieces. One piece runs from the air filter box to the front of the engine and the other
from the front of the engine to the rear of the engine locating on the throttle body. The front half
is manufactured from plastic and incorporates a number of resonator chambers. The rear part
of the duct is manufactured from cast aluminum.
Component Locations
260
1
Induction elbow
5
LH intercooler
2
Charge air ducts
6
Fuel rail adapter
3
Electronic throttle body
7
LH fuel rail
4
Injectors (8 of)
8
Supercharger
9
10
RH fuel rail
RH intercooler
DENSO ENGINE MANAGEMENT
Electronic Throttle
The V8 EMS incorporates an electric throttle control system. The electronic throttle body is
located on the air intake manifold in the engine compartment. The system comprises three main
components:
• Electronic throttle control valve
• APP
• ECM
When the accelerator pedal is depressed the APP sensor provides a change in the monitored
signals. The ECM compares this against an electronic “map” and moves the electronic throttle
valve via a PWM control signal which is in proportion to the APP angle signal. The system is
required to:
• Regulate the calculated intake air load based on the accelerator pedal sensor input signals
and programmed mapping.
• Monitor the drivers input request for cruise control operation.
• Automatically position the electronic throttle for accurate cruise control.
• Perform all dynamic stability control throttle control interventions.
• Monitor and carry out maximum engine and road speed cut out.
• Provide differing responses for differing Terrain response modes.
A software strategy within the ECM enables the throttle position to be calibrated each ignition
cycle. When the ignition is turned ON, the ECM performs a self test and calibration routine on
the electronic throttle by closing the throttle full, then opening again. This tests the default
position springs.
Electronic Throttle Pin Out Table
Pin No
Description
Pin No
Description
1
Motor +
4
Sensor 2 signal
2
Motor -
5
5 volt supply
3
Sensor ground
6
Sensor 1 signal
Electronic Throttle
261
DENSO ENGINE MANAGEMENT
Mass Air Flow/Inlet Air Temperature SENSOR (MAF/AT)
The MAF/IATis located in the clean air duct immediately after the air filter box.
The air mass flow is determined by the cooling effect of inlet air passing over a “hot film”
element contained within the device. The higher the air flow the greater the cooling effect and
the lower the electrical resistance of the “hot film” element. The ECM then uses this signal from
the MAF to calculate the air mass flowing into the engine.
The measured air mass flow is used in determining the fuel quantity to be injected in order to
maintain the stichometric air/fuel mixture required for correct operation of the engine and
exhaust catalysts. Should the device fail there is a software backup strategy that will be evoked
once a fault has been diagnosed.
The following symptoms may be observed if the sensor fails:
•
•
•
•
•
•
During driving the engine RPM might dip, before recovering.
Difficulty in starting or start - stall.
Poor throttle response / engine performance.
Lambda control and idle speed control halted.
Emissions incorrect.
AFM signal offset
The IAT sensor is integrated into the MAF meter. It is a temperature dependent resistor
(thermistor), i.e. the resistance of the sensor varies with temperature. This thermistor is a NTC
type element meaning that the sensor resistance decreases as the sensor temperature
increases. The sensor forms part of a voltage divider chain with an additional resistor in the
ECM. The voltage from this sensor changes as the sensor resistance changes, thus relating the
air temperature to the voltage measured by the ECM.
The ECM stores a 25 Degrees Celsius (77° F) default value for air temperature in the event of a
sensor failure.
262
DENSO ENGINE MANAGEMENT
Manifold Absolute Pressure Sensor (MAP)- Supercharger Inlet Pressure
The MAP sensor provides a voltage proportional to the absolute pressure in the supercharger
intake. This signal allows the load on the engine to be calculated and used within the internal
calculations of the ECM. The sensor is located below the electric throttle on the induction elbow.
MAP Pin Out Table
Pin No
Description
1
MAPsignal
2
Sensor supply
3
Not used
4
Sensor ground
The output signal from the MAP sensor, together with the CKP and IAT sensors, is used by the
ECM to calculate the amount of air induced into the cylinders. This enables the ECM to
determine ignition timing and fuel injection duration values.
The MAP sensor receives a 5V supply voltage from pin 48 of ECM connector C0634 and
provides an analogue signal to pin 38 of ECM connector C0634, which relates to the absolute
manifold pressure and allows the ECM to calculate engine load. The ECM provides a ground for
the sensor via pin 11 of ECM connector C0634.
If the MAP signal is missing, the ECM will substitute a default manifold pressure reading based
on crankshaft speed and throttle angle. The engine will continue to run with reduced drivability
and increased emissions, although this may not be immediately apparent to the driver. The
ECM will store fault codes which can be retrieved using T4.
Manifold Absolute Pressure Sensor (MAP)- Supercharger Inlet Pressure
263
DENSO ENGINE MANAGEMENT
Manifold Absolute Pressure And Temperature Sensor (TMAP)
The MAPT is located to the rear of the RH engine bank intercooler outlet. The sensor measures
the pressure and temperature of the inducted air prior to it entering the cylinders.
The sensor fits and seals using a radial ‘O’ ring seal directly to the inlet manifold.
The MAPT signal is used to retard the ignition timing relative to boost pressure. The intercooler
temperature is used for air charge density calculations and for intercooler diagnostic purposes.
264
Pin No
Description Input/Output
1
Boost pressure
Output
2
Sensor supply
Input
3
Intercooler outlet temperature
Output
4
Sensor ground
-
DENSO ENGINE MANAGEMENT
Crankshaft Position Sensor (CKP)
The crankshaft position sensor is mounted at the rear underside of the engine near the
transmission bell housing. Connection between the sensor and the harness is via a link harness
and a two-way connector. Both wires go directly to the ECM. The sensor produces the signal
which enables the ECM to determine the angle of the crankshaft, and the engine rpm. From
this, the point of ignition, fuel injection, etc. is calculated. If the signal wires are reversed a 3
degrees advance in timing will occur, as the electronics within the ECM uses the falling edge of
the signal waveform as its reference / timing point for each tooth.
The reluctor is pressed into the flywheel and has a "tooth" pattern based on 36 teeth at 10°
intervals and approximately 5° wide: one of the teeth is removed to provide a hardware
reference mark which is 30 degrees BTDC No.1 cylinder. Because of the crankshaft sensor's
orientation, the target wheel uses windows stamped into the face, rather than actual teeth.
The sensor operates by generating an output voltage caused by the change in magnetic field
that occurs as the windows pass in front of the sensor. The output voltage varies with the speed
of the windows passing the sensor, the higher the engine speed, the higher the output voltage.
Note that the output is also dependent on the air gap between the sensor and the teeth (the
larger the gap, the weaker the signal, the lower the output voltage). The ECM transmits the
engine speed to other vehicle control modules on CAN.
Crankshaft Position Sensor (CKP)
265
DENSO ENGINE MANAGEMENT
Camshaft Position Sensor (CMP)
Two sensors are located at the rear of the engine, in the cylinder head (one per bank), above
the rear cylinders. The sensors are Variable Reluctor Sensor (VRS) type, producing four pulses
for every two engine crankshaft revolutions. The sensing element is positioned between 0 and
2mm from the side of the cam gear wheel.
The camshaft timing wheel is a sintered component which has four teeth on it to enable the
EMS to detect cylinder identification. The signal is used for:
•
•
•
•
Cylinder recognition
Enabling sequential fuel injection
Knock control
Cylinder identification for diagnostic purposes.
Failure symptoms include:
• Ignition timing reverting to the base mapping, with no cylinder correction.
• Active knock control is disabled, along with its diagnostic (Safe ignition map - loss of performance).
• Quick cam/crank synchronisation on start disabled.
266
DENSO ENGINE MANAGEMENT
Engine Coolant Temperature Sensor (ECT)
The ECT sensor is located at the front of the engine at the rear of the thermostat housing. The
ECT sensor is a thermistor used to monitor the engine coolant temperature. The engine coolant
temperature sensor is vital to the correct running of the engine as a richer mixture is required at
lower block temperatures for good quality starts and smooth running, leaning off as the
temperature rises to maintain emissions and performance.
The sensor has an operating temperature range of -30 Degrees Celsius to 125 Degrees Celsius
(-22° F to 257° F). The maximum engine coolant temperature the ECM outputs on the CAN is
the 119 Degrees Celsius (246° F). When a defective coolant sensor is detected, the ECM uses
the oil temperature sensor value.
Engine Oil Temperature Sensor
Oil temperature is monitored through a temperature sensor mounted in the oil system. This
component is a NTC. The sensor is mounted next to the oil pressure sensor at the front of the
engine and locates into the oil filter bracket.
Engine Coolant Temperature Sensor (ECT)
267
DENSO ENGINE MANAGEMENT
Knock Sensors
The V8 EMS has two knock sensors located in the V of the engine, one per cylinder bank. The
sensors are connected to the ECM via a twisted pair.
The knock sensors produce a voltage signal in proportion to the amount of mechanical vibration
generated at each ignition point. Each sensor monitors the related cylinder bank.
The knock sensors incorporate a piezo-ceramic crystal. This crystal produces a voltage
whenever an outside force tries to deflect it, (i.e. exerts a mechanical load on it). When the
engine is running, the compression waves in the material of the cylinder block, caused by the
combustion of the fuel/air mixture within the cylinders, deflect the crystal and produce an output
voltage signal. The signals are supplied to the ECM, which compares them with `mapped'
signals stored in memory. From this, the ECM can determine when detonation occurs on
individual cylinders. When detonation is detected, the ECM retards the ignition timing on that
cylinder for a number of engine cycles, then gradually returns it to the original setting.
Care must be taken at all times to avoid damaging the knock sensors, but particularly during
removal and fitting procedures. The recommendations regarding torque and surface
preparation must be adhered to. The torque applied to the sensor and the quality of the surface
preparation both have an influence over the transfer of mechanical noise from the cylinder block
to the crystal.
The ECM uses the signals supplied by the knock sensors, in conjunction with the signal it
receives from the camshaft sensor, to determine the optimum ignition point for each cylinder.
The ignition point is set according to preprogrammed ignition maps stored within the ECM. The
ECM is programmed to use ignition maps for 98 RON premium specification fuel. It will also
function on 91 RON regular specification fuel and learn new adaptions. If the only fuel available
is of poor quality, or the customer switches to a lower grade of fuel after using a high grade for
a period of time, the engine may suffer slight pre-ignition for a short period. This amount of preignition will not damage the engine. This situation will be evident while the ECM learns and then
modifies its internal mapping to compensate for the variation in fuel quality. This feature is called
adaption. The ECM has the capability of adapting its fuel and ignition control outputs in
response to several sensor inputs.
The ECM will cancel closed loop control of the ignition system if the signal received from either
knock sensor becomes implausible. In these circumstances the ECM will default to a safe
ignition map. This measure ensures the engine will not become damaged if low quality fuel is
used. The MIL will not illuminate, although the driver may notice that the engine 'pinks' in some
driving conditions and displays a drop in performance and smoothness.
268
DENSO ENGINE MANAGEMENT
When a knock sensor fault is stored, the ECM will also store details of the engine speed, engine
load and the coolant temperature.
Accelerator Pedal Position Sensor (APP)
The APP sensors are located on the accelerator pedal assembly.
The APP sensors are used to determine the driver's request for vehicle speed, acceleration and
deceleration. This value is used by the ECM and the throttle is opened to the correct angle by
an electric motor integrated into the throttle body.
The APP Sensor signals are checked for range and plausibility. Two separate reference
voltages are supplied to the pedal. Should one sensor fail, the other is used as a 'limp – home'
input. In limp home mode due to an APP signal failure the ECM will limit the maximum engine
speed to 2000 rpm.
APP Pin Out Table
Pin No
Description
1
APP 1 ground
2
APP 1 demand
3
APP2 ground
4
Not used
5
APP 2 demand
6
Supply 2, 5 volt
7
Supply 1, 5 volt
8
Not used
Accelerator Pedal Position Sensor (APP)
269
DENSO ENGINE MANAGEMENT
Oxygen Sensors
There are four oxygen sensors located in the exhaust system. Two upstream before the
catalytic converter and two down stream after the catalytic converter. The sensor monitors the
level of oxygen in the exhaust gases and is used to control the fuel/air mixture. Positioning a
sensor in the stream of exhaust gasses from each bank enables the ECM to control the fueling
on each bank independently of the other, allowing much closer control of the air / fuel ratio and
catalyst conversion efficiency.
Upstream Oxygen Sensors
Downstream Oxygen Sensors
The oxygen sensors need to operate at high temperatures in order to function correctly. To
achieve the high temperatures required, the sensors are fitted with heater elements that are
controlled by a PWM signal from the ECM. The heater elements are operated immediately
following engine start and also during low load conditions when the temperature of the exhaust
gases is insufficient to maintain the required sensor temperatures. A non-functioning heater
delays the sensor’s readiness for closed loop control and influences emissions. The PWM duty
cycle is carefully controlled to prevent thermal shock to cold sensors.
UHEGO (Universal Heated Exhaust Gas Oxygen) sensors also known as Linear or "Wide
Band" sensors produces a constant voltage, with a variable current that is proportional to the
oxygen content. This allows closed loop fueling control to a target lambda, i.e. during engine
warm up (after the sensor has reached operating temperature and is ready for operation). This
improves emission control.
270
DENSO ENGINE MANAGEMENT
The HEGO sensor uses Zirconium technology that produces an output voltage dependant upon
the ratio of exhaust gas oxygen to the ambient oxygen. The device contains a Galvanic cell
surrounded by a gas permeable ceramic, the voltage of which depends upon the level of O2
defusing through. Nominal output voltage of the device for l =1 is 300 to 500m volts. As the fuel
mixture becomes richer (l<1) the voltage tends towards 900m volts and as it becomes leaner
(l>1) the voltage tends towards 0 volts. Maximum tip temperature is 1,000 Degrees Celsius
(1832° F) for a maximum of 100 hours.
Sensors age with mileage, increasing their response time to switch from rich to lean and lean to
rich. This increase in response time influences the ECM closed loop control and leads to
progressively increased emissions. Measuring the period of rich to lean and lean to rich
switching monitors the response rate of the upstream sensors.
Diagnosis of electrical faults is continually monitored in both the upstream and downstream
sensors. This is achieved by checking the signal against maximum and minimum threshold, for
open and short circuit conditions.
Oxygen sensors must be treated with the utmost care before and during the fitting process. The
sensors have ceramic material within them that can easily crack if dropped / banged or overtorqued. The sensors must be torqued to the required figure, (40-50Nm), with a calibrated
torque wrench. Care should be taken not to contaminate the sensor tip when anti-seize
compound is used on the thread. Heated sensor signal pins are tinned and universal are gold
plated. Mixing up sensors could contaminate the connectors and affect system performance.
Failure Modes
•
•
•
•
•
•
•
•
•
Mechanical fitting & integrity of the sensor.
Sensor open circuit / disconnected.
Short circuit to vehicle supply or ground.
Lambda ratio outside operating band.
Crossed sensors bank A & B.
Contamination from leaded fuel or other sources.
Change in sensor characteristic.
Harness damage.
Air leak into exhaust system.
Failure Symptoms
•
•
•
•
Default to Open Loop fueling for the particular cylinder bank
High CO reading.
Strong smell of H02S (rotten eggs) till default condition.
Excess Emissions.
It is possible to fit front and rear sensors in their opposite location. However the harness
connections are of different gender and color to ensure that the sensors cannot be incorrectly
connected. In addition to this the upstream sensors have two holes in the shroud, whereas the
down stream sensors have four holes in the shroud for the gas to pass through.
Oxygen Sensors
271
DENSO ENGINE MANAGEMENT
Ignition Coils
Component Location
1
Ignition coil wth combined amplifier
2
Capacitor
3
Spark plug
The V8 engine is fitted with eight plug-top coils that are driven directly by the ECM. This means
that the ECM, at the point where sufficient charge has built up, switches the primary circuit of
each coil and a spark is produced in the spark plug. The positive supply to the coil is fed from a
common fuse. Each coil contains a power stage to trigger the primary current. The ECM sends
a signal to each of the coils power stage to trigger the power stage switching. Each bank has a
feedback signal that is connected to each power stage. If the coil power stage has a failure the
feedback signal is not sent, causing the ECM to store a fault code appropriate to the failure.
The ECM calculates the dwell time depending on battery voltage and engine speed to ensure
constant secondary energy. This ensures sufficient secondary (spark) energy is always
available, without excessive primary current flow thus avoiding overheating or damage to the
coils.
Power for the ignition coils is supplied from the main relay and a fuse in the BJB. A capacitor is
connected in parallel with the power supplies to the ignition coils to suppress RFI (radio
frequency interference).
The individual cylinder spark timing is calculated from a variety of inputs:
•
•
•
•
•
Engine speed and load.
Engine temperature.
Knock control.
Auto gearbox shift control.
Idle speed control.
272
DENSO ENGINE MANAGEMENT
Ignition System Overview
NOTE: A = Hardwired connections
1
Battery
7
Ignition coil and spark plug 5
13
Ignition coil and spark plug 7
2
Fusible link 11E, BJB
8
Ignition coil and spark plug 2
14
Ignition coil and spark plug 6
3
Ignition switch
9
Ignition coil and spark plug 3
15
Ignition coil and spark plug 1
4
Fuse 25P, ignition feed, CJB
10
Ignition coil and spark plug 8
16
Fuse 6E, BJB
5
Fuse 60P, crank feed, CJB
11
Capacitor
17
Main relay
6
ECM
12
Ignition coil and spark plug 4
Ignition Coils
273
DENSO ENGINE MANAGEMENT
Viscous Fan Control
The ECM controls a viscous coupled fan to provide engine cooling. The ECM supplies the fan
with a PWM signal that controls the amount of slippage of the fan, thus providing the correct
amount of cooling fan speed and airflow. The EMS uses a Hall effect sensor to determine the
fan speed.
Terrain Response™
Terrain Response ™ system allows the driver to select a program which will provide the
optimum settings for traction and performance for prevailing terrain conditions.
As part of Terrain Response ™ there will be different throttle pedal progression maps
associated with different Terrain Response ™ modes. The two extremes are likely to be a sand
map (quick build up of torque with pedal travel) and grass/gravel/snow (very cautious build up of
torque).
The V8 Super Charged implementation of throttle progression is based on a fixed blend time.
The torque will blend from that on one map to that on the new map (for the same pedal position)
over a fixed time. This means blending will always take the same amount of time but when the
torque change is small the torque increase over time will be small, whilst if the torque change is
greater then the torque increase over time will be steeper. The resulting acceleration of the
vehicle will depend on the torque difference between the two maps as well as on the gear and
range selected.
Generator
The Generator has a multifunction voltage regulator for use in a 14V charging system with 6÷12
zener diode bridge rectifiers.
The ECM monitors the load on the electrical system via PWM signal and adjusts the generator
output to match the required load. The ECM also monitors the battery temperature to determine
the generator regulator set point. This characteristic is necessary to protect the battery; at low
temperatures battery charge acceptance is very poor so the voltage needs to be high to
maximize any rechargeability, but at high temperatures the charge voltage must be restricted to
prevent excessive gassing of the battery with consequent water loss.
274
DENSO ENGINE MANAGEMENT
The Generator has a smart charge capability that will reduce the electrical load on the
Generator reducing torque requirements, this is implemented to utilize the engine torque for
other purposes. This is achieved by monitoring three signals to the ECM:
• Generator sense (A sense), measures the battery voltage at the CJB.
• Generator communication (Alt Com) communicates desired Generator voltage set point
from ECM to Generator.
• Generator monitor (Alt Mon) communicates the extent of Generator current draw to ECM.
This signal also transmits faults to the ECM which will then sends a message to the instrument cluster on the CAN bus to illuminate the charge warning lamp.
Central Junction Box
The ECM is connected to ignition switch I and II. When the ignition is turned ON, 12V is applied
to the ignition sense input. The ECM then starts its power up routines and turns ON the ECM
main relay, the main power to the ECM and it's associated system components. When the
ignition is turned OFF the ECM will maintain its powered up state for up to 20 minutes while it
initiates its power down routine and on completion will turn OFF the ECM main relay. The ECM
will normally power down in approximately 60 seconds, do not disconcert the battery until the
ECM is completely powered down.
Fuel Tank and Lines
The major components of the 4.2L V8 supercharged fuel system comprise a fuel tank, a fuel
pump, a fuel filler assembly and two fuel level sensors.
The 4.2L V8 supercharged fuel system uses an electronic returnless fuel system which
comprises a pump module mounted in the fuel tank to deliver fuel at variable flow and pressure
to the fuel rails which supply fuel to all fuel injectors. The fuel pump operation is regulated by a
fuel pump driver module which is controlled by the engine management system. The control
module regulates the flow and pressure supplied by controlling the operation of the fuel pump
using a Pulse Width Modulation (PWM) output.
Central Junction Box
275
DENSO ENGINE MANAGEMENT
Fuel Delivery System Component Location
NOTE: 4.2L V8 Supercharged
276
1
Filler cap and lanyard
8
Mounting screw (6 off)
15
Tank breather pipe
2
Breather line 'Y' piece to charcoal
canister
9
Cover
16
Fuel filler pipe
3
Charcoal canister purge line
10
Cradle
17
Charcoal canister vent pipe
4
Charcoal canister
11
Pipe - Fuel pump to engine (feed)
18
DMTL pump (NAS only)
5
Rear differential breather pipe
12
Pipe - EVAP purge valve to charcoal canister
19
DMTL filter (NAS only)
6
Tank breather pipe
13
Fuel tank
7
Heat shield
14
Fuel pump module assembly
DENSO ENGINE MANAGEMENT
Purge Valve
1
Fuel feed jump hose (Ref. only)
4
Bracket
2
Purge hose connector
5
Purge hose
3
Purge valve
6
Electronic throttle
7
Induction elbow
The purge valve is located at the rear of the engine, on a bracket which is attached to the
transmission bell housing. The purge hose is routed from the purge valve, along the left hand
side of the air intake manifold, to the induction elbow assembly which locates the electronic
throttle.
The purge hose is connected, at the right hand rear of the engine, with a quick release coupling
to the purge line which runs parallel with the fuel feed line along the top of the fuel tank to the
charcoal canister.
The purge hose continues from the purge valve and is routed to a connection on the air intake
elbow assembly. The hose is connected to the elbow with a quick release connector.
The purge valve is located on a bracket on the bell housing and is secured with a single bolt.
The purge valve is a solenoid operated valve which is closed when de-energised. The valve is
controlled by the Engine Control Module (ECM) and is operated when engine operating
conditions are correct to allow purging of the charcoal canister.
Purge Valve
277
DENSO ENGINE MANAGEMENT
The ECM keeps the purge valve closed (de-energised) below a predetermined engine coolant
temperature and engine speed to protect the engine tune and catalytic converter performance.
If the purge valve is opened during cold running conditions or at engine idle speed, the
additional fuel vapor can cause the engine to have erratic idle speed or even stall. When engine
operating conditions are correct, the ECM opens the purge valve (energised) and the
depression at the inlet manifold draws a fuel vapor and fresh air mix from the charcoal canister.
When the purging process is active, fresh air is drawn into the charcoal canister via the DMTL
pump atmospheric vent connection and its filter on NAS vehicles and via the atmospheric vent
hose connection and the spider trap on non NAS vehicles.
On NAS vehicles the system does not include a pressure test point. Pressure testing of the
purge valve hose is achieved by disconnecting the purge valve joint on the underside of the
vehicle, forward of the fuel tank and connecting a special tool to allow the system to be pressure
tested. The test performs a pressure test on the purge hose connection forward of the fuel tank
back to the charcoal canister. The special tool is then connected to the purge hose connection
forward of the fuel tank to perform a pressure test on the purge hose to the purge valve.
Fuel Pump
The submersible electric fuel pump is attached to a carrier and is located at the bottom of the
swirl pot inside the fuel tank. The fuel pressure regulator, which controls the fuel pressure in the
feed pipe to fuel rail, is located in the fuel manifold in the fuel tank.
Fuel Pump Relay
The ECM controls the fuel pump relay which in turn controls the power supply to the fuel pump
driver module. The ECM energizes the relay ON with ignition ON, via pin A95 of the ECM.
278
DENSO ENGINE MANAGEMENT
Fuel Pump Driver Module
The fuel pump driver module is located in the rear LH quarter adjacent to the parking aid control
module.
The fuel pump is control by the ECM. The ECM sends a PWM signal to the fuel pump driver
module from pin B20 of the ECM, the frequency of the signal determines the duty cycle of the
pump. the PWM signal to the pump represents half the ON time of the pump. If the ECM
transmits a 50% on time the fuel pump driver module drives the pump at 100%. If the ECM
transmits a 5% ON time the fuel pump driver module drives the pump at 10%. The fuel pump
driver module will only turn the fuel pump ON if it receive a valid signal between 4% and 50%.
When The ECM requires the fuel pump to be turned OFF the ECM transmits a duty cycle signal
of 75%.
The status of the fuel pump driver module is monitored by the ECM on pin B21. Any errors can
be retrieved from The ECM. The fuel pump driver module cannot be interrogated for diagnostic
purposes.
The MAP controls The fuel pump driver module in response to inputs from the fuel rail pressure
sensor, MAP and the MAF/IAT sensor.
The fuel pressure range is 0.9 - 5.4 bar (13 - 78 psi).
Harness Connector C2369 pin out details
Pin No
Description
Input/Output
1
Pump +
Output
2
Pump -
-
3
ECMPWM signal
Input
4
Diagnostic signal
Output
5
Battery voltage
Input
6
GND
-
Fuel Pump Driver Module
279
DENSO ENGINE MANAGEMENT
Fuel Rails
1
RH fuel pressure accumulator
4
Fuel temperature sensor
7
LH fuel rail
2
Injectors (8 of)
5
Fuel pressure sensor
8
LH fuel pressure accumulator
3
RH fuel rail
6
Fuel supply
9
Fuel supply cross over pipe
Four fuel injectors are installed in each intercooler adapter and are connected to the fuel rail. 'O'
ring seals are used to seal the injectors in the fuel rails and the intercooler adapters.
A fuel pressure accumulator is attached to each of the fuel rails.
Fuel Rail Pressure Sensor
The fuel rail pressure sensor is located on top of the fuel rail adjacent to the fuel inlet. The fuel
rail pressure sensor measures the pressure of the fuel in the fuel rail. This input is then used by
the ECM which commands the FPDM to control the amount of fuel delivered to the fuel rail.
280
DENSO ENGINE MANAGEMENT
Fuel Rail Temperature Sensor
The fuel rail temperature sensor measures the temperature of the fuel in the fuel rail. This input
is then used to deliver the correct quantity of fuel to the engine. The sensors operating range is
-40 Degrees Celsius to 150 Degrees Celsius (-40° F to 302° F). The fuel rail temperature
sensor is fitted on the rear of the right hand bank (bank A) fuel rail.
Fuel Injectors
The engine has 8 fuel injectors (one per cylinder), each injector is directly driven by the ECM.
The injectors are fed by a common fuel rail as part of a ‘return less’ fuel system. The fuel rail
pressure is regulated to 4.5 bar by a fuel pressure regulator which is integral to the fuel pump
module, within the fuel tank. The injectors can be checked by resistance checks. The ECM
monitors the output power stages of the injector drivers for electrical faults.
The injectors have a resistance of 13.8 Ohms ± 0.7 Ohms @ 20 Degrees Celsius (68° F)
Fuel Rail Temperature Sensor
281
DENSO ENGINE MANAGEMENT
282
DENSO ENGINE MANAGEMENT
Denso ECM Pinouts
Connector C0634
Pin
No
Wire
Color
Description
Input/
Output
1
Y
Not used
-
2
GB
Not used
-
3
WG
Generator monitor
Input
4
Not used
-
5
Not used
-
6
B
CKP sensor -
Input
7
R
CMP sensor 1GND
-
8
N
CMP sensor 2GND
-
Not used
-
9
10
BG
TP sensor GND
-
11
BG
MAP sensor ground
-
12
GB
FRP sensor ground
-
13
Not used
-
14
Not used
Input
ECT ground
-
Not used
MAF ground
-
Not used
15
BG
16
17
Pin
No
Wire
Color
Description
Input/
Output
23
Y
Oil temperature sensor
Input
24
MAPT sensor 5v ref
Output
25
Not used
-
26
N
UHEGO sensor bank B
signal
Input
27
G
UHEGO sensor bank B
GND
-
28
R
UHEGO sensor bank A
signal
Input
29
Y
UHEGO sensor bank A
GND
-
30
O
CKP sensor +
Input
31
Not used
-
32
Not used
-
33
G
CMP signal bank B
Input
34
Y
CMP signal bank A
Input
35
Not used
-
36
Not used
-
37
Not used
-
-
38
MAPsignal
Input
18
BP
MAF sensor ground
-
39
IAT
Input
19
B
Knock sensor 1A ground
-
40
Not used
Input
20
S
Knock sensor 1B ground
-
41
Not used
Input
21
Not used
-
42
N
Knock sensor 1 A +
Input
22
Not used
-
43
G
Knock sensor 1 B +
Input
Denso ECM Pinouts
283
DENSO ENGINE MANAGEMENT
Pin
No
Description
Input/
Output
Pin
No
Wire
Color
Description
Input/
Output
44
Not used
-
72
OY
Output
45
Not used
-
Electric throttle 5V reference
Fuel rail temperature sensor
Input
Not used
-
Fuel rail pressure sensor
5 V ref voltage
Output
MAP sensor 5 V ref voltage
Output
Not used
46
Wire
Color
YR
47
48
OY
49
73
74
RW
Throttle valve open direction -
Output
75
GW
Throttle valve open direction +
Output
76
RU
UHEGO Heater bank A
Output
-
77
RW
UHEGO Heater bank B
Output
50
YU
Not used
-
78
BG
Injector cylinder 1A
Output
51
YR
Not used
-
79
BR
Injector cylinder 1B
Output
52
YG
Not used
-
80
BP
Injector cylinder 2A
Output
53
YU
Not used
-
81
BO
Injector cylinder 2B
Output
54
YR
Ignition coil cylinder 4B
Output
82
BG
Injector cylinder 3A
Output
55
GR
Ignition coil cylinder 4A
Output
83
U
Injector cylinder 3B
Output
56
GR
Ignition coil cylinder 3B
Output
84
BW
Injector cylinder 4A
Output
57
YR
Ignition coil cylinder 3A
Output
85
UY
Injector cylinder 4B
Output
58
GW
Ignition coil cylinder 2B
Output
86
Y
Not used
-
59
Y
Ignition coil cylinder 2A
Output
87
YU
Not used
-
60
GW
Ignition coil cylinder 1B
Output
88
Not used
-
61
GU
Ignition coil cylinder 1A
Output
89
Not used
-
62
GB
Ignition failure signal bank
A
Input
90
Not used
-
91
Not used
-
63
Y
Viscous fan speed monitor
Input
64
YB
Ignition failure signal bank
B
Input
65
R
TP sensor 1
Input
66
U
MAF
Input
67
Y
TP sensor 2
Input
68
UY
ECT
Input
69
BP
Inlet manifold boost pressure
Input
70
GW
MAF
Input
Fuel rail pressure sensor
signal
Input
71
284
92
UY
Purge valve
Output
93
B
Viscous fan request
Output
94
UB
E box fan
Output
95
YN
FPDM power
Output
96
WR
Generator control
Output
DENSO ENGINE MANAGEMENT
Connector C0635
Pin
No
Wire
Color
Description
Input/
Output
1
B
Signal ground 1
-
2
B
Power ground 1
-
3
B
Power ground 3
-
4
NO
Power ground 2
-
5
B
ECM power
Output
6
RG
Electric throttle power
Input
7
YLG
APP sensor ground 1
-
8
BG
APP sensor ground 2
-
9
Not used
-
10
Not used
11
Pin
No
Wire
Color
Description
Input/
Output
24
RB
APP sensor 1 signal
Output
25
U
HEGO sensor A
Input
26
WU
HEGO sensor B
Input
Not used
-
RCM
Input
Not used
-
Ignition switch
Input
Not used
-
27
28
YG
29
30
BO
31
32
R
APP sensor 1 5V reference
Output
-
33
Y
DMTL pump
Output
Not used
-
34
RB
HEGO sensor B GND
-
12
Not used
-
35
R
Speed control switch -
Output
13
Not used
-
36
PU
Speed control switch +
Input
14
Not used
-
37
Not used
-
APP sensor 2 demand
Input
15
GO
Park/ Neutral signal
Input
38
16
NU
EMS relay
Output
39
Not used
-
17
WR
Crank request
Input
40
Not used
-
Not used
-
41
Brake pedal switch
Input
APP sensor 2 5V ref
Output
42
Not used
-
20
FPDM control
Output
43
Not used
-
21
FPDM monitor
Input
44
YB
CAN out -
Input/output
45
YB
CAN in -
Input/output
18
19
OY
22
RB
HEGO sensor A GND
-
23
G
DMTL heater
Output
Denso ECM Pinouts
U
GP
285
DENSO ENGINE MANAGEMENT
Pin
No
Wire
Color
Description
Input/
Output
46
WO
HEGO heater A
Output
47
G
HEGO heater B
Output
48
R
DMTL valve
Output
Not used
-
49
50
G
Vacuum pump relay
Output
51
UR
Starter relay
Output
52
Not used
-
53
Not used
-
Battery voltage
Input
55
Not used
-
56
Not used
-
54
NO
57
YN
CAN out +
Input/output
58
YN
CAN in +
Input/output
286
GLOSSARY
GLOSSARY
Air Cleaner (ACL): Air Cleaner
Air Cleaner Filter (ACL Filter): Air Cleaner Filter Element
Air Conditioning Clutch (ACC): Air Conditioning Clutch signal commands status of the A/C
clutch
Accelerator Pedal (AP): Accelerator Pedal
Battery Positive Voltage (B+): The positive voltage from the battery or any circuit connected
directly to the battery
Brake On/Off (BOO): Brake On/Off signal; indicates the position of the brake pedal
Bypass Air (BPA): Bypass Air is the mechanical control of throttle bypass air
Camshaft Position Sensor (CMP Sensor): Camshaft Position Sensor indicates camshaft
position
Canister Purge (CANP): Canister Purge solenoid controls purging of the EVAP canister
Closed Loop (CL): Closed Loop controls the engine operation when the engine operates in
closed loop fuel control (most normal driving)
Crankshaft Position Sensor (CKP Sensor): Crankshaft Position sensor indicates crankshaft
position
Data Link Connector (DLC): Data Link Connector provides access and/or control of the
vehicle information, operating conditions and diagnostic information
Diagnostic System Manager (DSM): Software that manages the operation of OBD II monitors.
Diagnostic Trouble Code (DTC): Diagnostic Trouble Code is an alpha/numeric identifier for
afault condition identified by the On-Board Diagnostic System
Direct Ignition System (DIS System): Direct Ignition is a system in which the ignition coil
secondary circuit is dedicated to specific spark plugs without the use of a distributor.
Engine Control Module (ECM): Engine ECU: Electronic Control Unit
Engine Coolant Temperature (ECT): Engine Coolant Temperature signal and sensor indicates
the temperature of the engine coolant
Engine Coolant Temperature Sensor (ECT Sensor): CTS: Coolant Temperature Sensor
Engine Speed (RPM): Rotational speed of the engine crankshaft
Evaporative Emission System (EVAP System): Evaporative Emission is a system to prevent
vapor from escaping into the atmosphere. The Land Rover system includes a charcoal canister
to store fuel vapors
Fan Control (FC): Fan Control is for controlling the engine cooling fan
Freeze Frame: OBD II diagnostic screen where that indicates the exact operating conditions
when the MIL was illuminated.
GLOSSARY
287
GLOSSARY
Fuel Pump (FP): Fuel Pump is a pump used to deliver fuel to the engine
Generator (GEN): Generator (formerly alternator) is a rotating machine designed to convert
mechanical energy to electric energy
GEMS: Generic Engine Management System
Ground (GND): Ground is an electrical conductor used as a common return for an electrical
circuit(s) and with a zero relative potential
Heated Oxygen Sensor (H02S): Heated Oxygen sensor (formerly HEGO) is an Oxygen
Sensor (02S) that is electrically heated
Idle Air Control (IAC): Idle Air Control indicates electrical control of throttle bypass air
Ignition Control Module (IC Module): Ignition Control Module is the logic module that controls
the ignition system
Inertia Fuel Shutoff (IFS): Inertia Fuel Shutoff is a switch that shuts off the fuel delivery system
when activated by predetermined acceleration force
Intake Air Temperature Sensor (IAT Sensor): Also called Air Charge Temperature sensor
Knock Sensor (KS): Detects spark knock within a certain frequency and intensity range, and
produces an electrical signal to the PCM
Lambda Sensor: Oxygen sensor
Long Term Fuel Trim (LT Fuel Trim): Long Term Fuel Trim
Malfunction Indicator Lamp (MIL): Malfunction Indicator Lamp illuminates on the instrument
panel when an emission related component or monitor fails
Manifold Absolute Pressure (MAP): Manifold Absolute Pressure is the absolute pressure of
the intake manifold air
Manual Lever Position (MLP): Manual Lever Position sensor signal now called Transmission
Range (TR)
Mass Air Flow (MAF): Mass Air Flow is a sensor which provides information on the mass flow
rate of the intake air to the engine
Multiport Fuel Injection (MFI): Multiport Fuel Injector is a fuel-delivery system in which each
cylinder is individually fueled
On-Board Diagnostic System (OBD): System that provides self-diagnostics of engine
management system components.
Open Loop (OL): Open Loop
P1000 Code: Appears when the vehicle has not completed all OBD II monitors since the GEMS
memory was last cleared.
Park/Neutral Position Switch (PNP Switch): Park/Neutral Position sensor indicates the
selected non-drive modes of the transmission
288
GLOSSARY
Power Steering Pressure (PSP): Power Steering Pressure switch indicates a pressure limit in
the power steering system
Sequential Multiport Fuel Injection (SFI): Sequential Multiport Fuel Injector is a multiport fuel
delivery system in which each injector is individually energized and timed
Short Term Fuel Trim (SFT): Short term fuel trim, injector control strategy
Stoichiometric Ratio: Fuel mixture at which the ratio of air and fuel (14.7 to 1) permits
complete burning.
Tachometer (TACH): Tachometer is a circuit that provides input for an electronic tachometer
display
Three Way Catalyst Converter (TWC): Catalytic Converter
Throttle Position Output (TPOUT): Signal provided by the TP sensor
Throttle Position Sensor (TP Sensor): TPS: Throttle Body Sensor
Transmission Control Module (TCM): Electronic Control Module responsible for transmission
operation
Vehicle Speed Sensor (VSS): Vehicle Speed Sensor is a sensor which provides vehicle speed
information
Warm-up Cycle: Engine operation after an engine OFF period, where coolant temperature
rises to at least 40° F and reaches at least 160° F.
Wide Open Throttle (WOT): A condition of maximum air flow through the throttle valve
GLOSSARY
289
GLOSSARY
290
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement