DENSO Diesel Injection Pump SERVICE MANUAL

Diesel Injection Pump
SERVICE MANUAL
COMMON RAIL SYSTEM (CRS)
OPERATION
September, 2007
00400534E
© 2007 DENSO CORPORATION
All Rights Reserved. This book may not be reproduced
or copied, in whole or in part, without the written
permission of the publisher.
Revision History
Revision History
Date
Revision Contents
2007. 09
• SCV: Explanation of compact SCV added to "Suction Control Valve (SCV)". (Operation: Refer
to page 1-30.)
• "Repair" section added.
Table of Contents
Table of Contents
Operation Section
1. GENERAL DESCRIPTION
1.1
Changes In Environment Surrounding The Diesel Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2
Demands On Fuel Injection System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3
Types Of And Transitions In ECD (ELECTRONICALLY CONTROLLED DIESEL) Systems . . . . . . . . . . . . . . 1-3
1.4
Common Rail System Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.5
Common Rail System And Supply Pump Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.6
Injector Transitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.7
Common Rail System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
2. COMMON RAIL SYSTEM OUTLINE
2.1
Layout of Main Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
3. SUPPLY PUMP DESCRIPTION
3.1
HP0 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
3.2
HP2 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
3.3
HP3 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
3.4
HP4 Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41
4. RAIL DESCCRIPTION
4.1
Rail Functions and Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46
4.2
Component Part Construction and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46
5. INJECTOR DESCRIPTION
5.1
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-50
5.2
Injector Construction and Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51
5.3
Injector Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54
5.4
Injector Actuation Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-54
5.5
Other Injector Component Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-56
6. DESCRIPTION OF CONTROL SYSTEM COMPONENTS
6.1
Engine Control System Diagram (Reference) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-59
6.2
Engine ECU (Electronic Control Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-60
6.3
EDU (Electronic Driving Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-60
6.4
Various Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61
7. CONTROL SYSTEM
7.1
Fuel Injection Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-66
7.2
E-EGR System (Electric-Exhaust Gas Recirculation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-76
7.3
Electronically Controlled Throttle (Not Made By DENSO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-78
7.4
Exhaust Gas Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-79
7.5
DPF System (Diesel Particulate Filter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-80
7.6
DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-82
Table of Contents
8. DIAGNOSIS
8.1
Outline Of The Diagnostic Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-83
8.2
Diagnosis Inspection Using DST-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-83
8.3
Diagnosis Inspection Using The MIL (Malfunction Indicator Light) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-84
8.4
Throttle Body Function Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-86
9. END OF VOLUME MATERIALS
9.1
Particulate Matter (PM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-87
9.2
Common Rail Type Fuel Injection System Development History And The World’s Manufacturers. . . . . . . . . 1-87
9.3
Higher Injection Pressure, Optimized Injection Rates, Higher Injection Timing Control Precision, Higher Injection
Quantity Control Precision. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-88
9.4
Image Of Combustion Chamber Interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-90
Repair Section
1. DIESEL ENGINE MALFUNCTIONS AND DIAGNOSTIC METHODS (BASIC KNOWLEDGE)
1.1
Combustion State and Malfunction Cause . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-91
1.2
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-92
2. DIAGNOSIS OVERVIEW
2.1
Diagnostic Work Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-93
2.2
Inquiries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-94
2.3
Non-Reoccurring Malfunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-96
3. DTC READING (FOR TOYOTA VEHICLES)
3.1
DST-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98
3.2
DTC Check (Code Reading via the DST-2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98
3.3
DTC Memory Erasure (via the DST-2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-98
4. TROUBLESHOOTING BY SYSTEM
4.1
Intake System Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-99
4.2
Fuel System Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-99
4.3
Basics of Electrical/Electronic Circuit Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-102
5. TROUBLESHOOTING
5.1
Troubleshooting According to Malfunction Symptom (for TOYOTA Vehicles). . . . . . . . . . . . . . . . . . . . . . . . 2-107
5.2
Other Malfunction Symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122
6. DIAGNOSIS CODES (DTC)
6.1
DTC Chart (Example) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-124
Operation Section
1– 1
1. GENERAL DESCRIPTION
1.1 Changes In Environment Surrounding The Diesel Engine
z Throughout the world, there is a desperate need to improve vehicle fuel economy for the purposes of preventing global
warming and reducing exhaust gas emissions that affect human health. Diesel engine vehicles are highly acclaimed in
Europe, due to the good fuel economy that diesel fuel offers. On the other hand, the "nitrogen oxides (NOx)" and "particulate matter (PM)" contained in the exhaust gas must be greatly reduced to meet exhaust gas regulations, and technology is being actively developed for the sake of improved fuel economy and reduced exhaust gases.
(1) Demands on Diesel Vehicles
• Reduce exhaust gases (NOx, PM, carbon monoxide (CO), hydrocarbon (HC) and smoke).
• Improve fuel economy.
• Reduce noise.
• Improve power output and driving performance.
(2) Transition of Exhaust Gas Regulations (Example of Large Vehicle Diesel Regulations)
• The EURO IV regulations take effect in Europe from 2005, and the 2004 MY regulations take effect in North America
from 2004. Furthermore, the EURO V regulations will take effect in Europe from 2008, and the 2007 MY regulations
will take effect in North America from 2007. Through these measures, PM and NOx emissions are being reduced in
stages.
NOx
PM
g/kWh
g/kWh
Europe
Europe
EURO
EURO
EURO
EURO
EURO
EURO
North America
1998 MY
2004 MY
2007 MY
3.5
North
America
0.11
0.13
1998 MY
0.03
2004 2005
2.7
2.0
2004 MY
0.27
0.013
2007 2008
2007 MY
2004 2005
2007 2008
Q000989E
1– 2
Operation Section
1.2 Demands On Fuel Injection System
z In order to address the various demands that are imposed on diesel vehicles, the fuel injection system (including the
injection pump and nozzles) plays a significant role because it directly affects the performance of the engine and the
vehicle. Some of the demands are: higher injection pressure, optimized injection rate, higher precision of injection timing
control, and higher precision of injection quantity control.
< NOTE >
z For further information on higher injection pressure, optimized injection rate, higher precision of injection timing control,
and higher precision of injection quantity control, see the material at the end of this document.
Operation Section
1– 3
1.3 Types Of And Transitions In ECD (ELECTRONICALLY CONTROLLED
DIESEL) Systems
z ECD systems include the ECD-V series (V3, V4, and V5) which implements electronic control through distributed pumps
(VE type pumps), and common rail systems made up of a supply pump, rail, and injectors. Types are the ECD-V3 and
V5 for passenger cars and RVs, the ECD-V4 that can also support small trucks, common rail systems for trucks, and
common rail systems for passenger cars and RVs. In addition, there are 2nd-generation common rail systems that support both large vehicle and passenger car applications. The chart below shows the characteristics of these systems.
'85
'90
'95
'00
ECD-V1
ECD-V3
· The world's first SPV (electromagnetic
spill valve system) is used for fuel
injection quantity control, so the
quantity injected by each cylinder can
be controlled.
· Maximum Injection Pressure 60 MPa
System
Types and
Transitions
ECD-V4
ECD-V5
· Inner Cam Pumping Mechanism
· Maximum Injection Pressure 130 MPa
· Uses pilot injection to reduce the
engine combustion noise.
· Maximum Injection Pressure
100 MPa
ECD-V4
ECD-V5
ECD-V3
Large Vehicle Common Rail
(HP0)
Passenger Car Common Rail
(HP2)
Common Rail System
· Fuel raised to high pressure by the
supply pump is temporarily
accumulated in the rail, then injected
after the injector is energized.
· Uses pilot injection to reduce the
engine combustion noise
· Maximum Injection Pressure 180 MPa
Supply Pump
Injector
Rail
Q000750E
Operation Section
1– 4
1.4 Common Rail System Characteristics
z The common rail system uses a type of accumulation chamber called a rail to store pressurized fuel, and injectors that
contain electronically controlled solenoid valves to inject the pressurized fuel into the cylinders.
z Because the engine ECU controls the injection system (including the injection pressure, injection rate, and injection timing), the injection system is independent and thus unaffected by the engine speed or load.
z Because the engine ECU can control injection quantity and timing to a high level of precision, even multi-injection (multiple fuel injections in one injection stroke) is possible.
z This ensures a stable injection pressure at all times, even in the low engine speed range, and dramatically decreases
the amount of black smoke ordinarily emitted by a diesel engine during start-up and acceleration. As a result, exhaust
gas emissions are cleaner and reduced, and higher power output is achieved.
(1) Features of Injection Control
Injection Pressure Control
• Enables high-pressure injection even at low engine speeds.
• Optimizes control to minimize particulate matter and NOx emissions.
Injection Timing Control
• Enables finely tuned optimized control in accordance with driving conditions.
Injection Rate Control
• Pilot injection control injects a small amount of fuel before the main injection.
Common Rail System
Injection Timing Control
Pilot injection
Injection Rate
Optimized and Higher Pressure
· Injection pressure is more than double the current
pressure, which makes it possible to greatly reduce
particulate matter.
Electronic Control Type
Injec
tion
Speed
Injection Pressure
Advance Angle
Particulate
Injection Pressure
Common Rail System
Conventional
Pump
Injection Rate Control
Qua
ntity
Speed
After-Injection
Pre-Injection
Post-Injection
Main Injection
Crankshaft Angle
Injection Quantity Control
Cylinder Injection Quantity Correction
Injection Quantity
Injection Pressure Control
1
3 2 4
Q000751E
Operation Section
1– 5
1.5 Common Rail System And Supply Pump Transitions
z The world's first common rail system for trucks was introduced in 1995. In 1999, the common rail system for passenger
cars (the HP2 supply pump) was introduced, and then in 2001 a common rail system using the HP3 pump (a lighter and
more compact supply pump) was introduced. In 2004, the three-cylinder HP4 based on the HP3 was introduced.
1996
Common Rail
System
1998
2000
2002
1st Generation Common Rail System
HP0
2004
2006
2nd Generation Common Rail System
120MPa
Large Trucks
HP4
Medium-Size Trucks
Pre-Stroke Quantity Adjustment
HP3
180MPa
Suction Quantity
Adjustment
HP2
Compact Trucks
180MPa
Suction Quantity
Adjustment
Passenger Vehicles
Suction Quantity
Adjustment
135MPa
Q000752E
1.6 Injector Transitions
97
98
99
00
1st Generation
X1
01
02
03
2nd Generation
G2
· 120MPa
· Pilot Injection
· 180MPa
· Multi-Injection
X2
· 135MPa
· Pilot Injection
Q000753E
1– 6
Operation Section
1.7 Common Rail System Configuration
z The common rail control system can be broadly divided into the following four areas: sensors, engine ECU, EDU, and
actuators.
Sensors
z Detect the condition of the engine and the pump.
Engine ECU
z Receives signals from the sensors, calculates the proper injection quantity and injection timing for optimal engine operation, and sends the appropriate signals to the actuators.
EDU
z Enables the injectors to be actuated at high speeds. There are also types with charge circuits within the ECU that serve
the same role as the EDU. In this case, there is no EDU.
Actuators
z Operate to provide optimal injection quantity and injection timing in accordance with the signals received from the engine ECU.
Engine Speed Sensor /
TDC (G) Sensor
Supply Pump
(SCV: Suction Control Valve)
EDU
Accelerator Position Sensor
Injector
Engine ECU
Other Sensors
and Switches
Other Actuators
Diagnosis
Q000754E
Operation Section
1– 7
2. COMMON RAIL SYSTEM OUTLINE
2.1 Layout of Main Components
z Common rail systems are mainly made up of the supply pump, rail, and injectors. There are the following types according to the supply pump used.
(1) HP0 Type
• This system is the first common rail system that DENSO commercialized. It uses an HP0 type supply pump and is
mounted in large trucks and large buses.
Exterior View of Main System Components
Rail
Supply Pump (HP0 Type)
Injector
Q000755E
Configuration of Main System Components (Example of HP0)
Engine ECU
Accelerator
Position Sensor
Rail
Fuel Temperature
Sensor
Rail Pressure Sensor
Injector
Coolant Temperature
Sensor
PCV (Pump Control Valve)
Supply Pump
Cylinder
Recognition Sensor
(TDC (G) Sensor)
Crankshaft Position Sensor (Engine Speed Sensor)
Q000756E
1– 8
Operation Section
(2) HP2 Type
• This system uses a type of HP2 supply pump that has been made lighter and more compact, and is the common rail
system for passenger cars and RVs instead of the ECD-V3.
Exterior View of Main System Components
Rail
Supply Pump (HP2 Type)
Injector
Q000757E
Mounting Diagram of Main System Components
EGR Valve
Intake Air Pressure Sensor
Engine ECU
Accelerator Position Sensor
Injector
Rail Pressure Sensor
E-VRV
Coolant Temperature
Sensor
Intake Air Temperature
Sensor
Crankshaft Position Sensor
(Engine Speed Sensor)
EDU (Electronic Driving Unit)
Rail
Supply Pump
Cylinder Recognition Sensor
(TDC (G) Sensor)
Q000758E
Operation Section
1– 9
Overall System Flow (Fuel)
Various Sensors
Engine
ECU
EDU
Rail Pressure Sensor
Rail
TWV
Pressure
Limiter
Regulating Valve
Fuel Filter
Delivery Valve
Injector
Supply Pump
SCV
(Suction
Control
Valve)
Check Valve
Feed Pump
Plunger
Inner Cam
: Flow of Injection Fuel
: Flow of Leak Fuel
Fuel Tank
Q000926E
Operation Section
1– 10
(3) HP3 Type, HP4 Type
HP3 Type
• This system uses an HP3 type supply pump that is compact, lightweight and provides higher pressure. It is mostly
mounted in passenger cars and small trucks.
HP4 Type
• This system is basically the same as the HP3 type, however it uses the HP4 type supply pump, which has an increased pumping quantity to handle larger engines. This system is mostly mounted in medium-size trucks.
Exterior View of Main System Components
Rail
HP3
HP4
Supply Pump
Injector
Q000759E
Mounting Diagram for Main System Components
Engine ECU
Intake Air Throttle Body
EGR Valve E-VRV for EGR
Pressure
Sensor
DLC3 Connector
Airflow Meter
(with Intake Air
Temperature Sensor)
Accelerator Position Sensor
EDU
R/B
EGR Shut-Off VSV
Rail Pressure Sensor Coolant Temperature Sensor
Pressure Discharge Valve
Injector
Supply Pump
Crankshaft Position Sensor
(Engine Speed Sensor)
HP3
HP4
Fuel Temperature
Sensor
SCV
(Suction Control
Valve)
Cylinder Recognition Sensor
(TDC (G) Sensor)
SCV
(Suction Control
Valve)
Fuel Temperature
Sensor
Q000760E
Operation Section
1– 11
Overall System Flow (Fuel)
EDU
Various
Sensors
ECU
Pressure Discharge Valve
Rail
Pressure Limiter
Rail Pressure Sensor
Delivery
Valve
Supply Pump
(HP3 or HP4)
Injector
Plunger
SCV
(Suction
Control Valve)
Feed Pump
: Flow of Injection Fuel
: Flow of Leak Fuel
Fuel Filter
Fuel Tank
Q000927E
1– 12
Operation Section
3. SUPPLY PUMP DESCRIPTION
3.1 HP0 Type
(1) Construction and Characteristics
• The HP0 supply pump is mainly made up of a pumping system as in conventional in-line pumps (two cylinders), the
PCV (Pump Control Valve) for controlling the fuel discharge quantity, the cylinder recognition sensor {TDC (G) sensor}, and the feed pump.
• It supports the number of engine cylinders by changing the number of peaks on the cam. The supply pump rotates at
half the speed of the engine. The relationship between the number of engine cylinders and the supply pump pumping
is as shown in the table below.
Number of Engine Cylinders
Speed Ratio
(Pump: Engine)
Supply Pump
Number of
Cylinders
4 Cylinders
6 Cylinders
1:2
2
8 Cylinders
Number of Pumping Rotations for 1
Cam Peaks
Cycle of the Engine (2 Rotations)
2
4
3
6
4
8
• By increasing the number of cam peaks to handle the number of engine cylinders, a compact, two-cylinder pump unit
is achieved. Furthermore, because this pump has the same number of pumping strokes as injections, it maintains a
smooth and stable rail pressure.
PCV (Pump Control Valve)
Delivery Valve
Element
Overflow Valve
Cylinder Recognition Sensor
(TDC (G) Sensor)
Feed Pump
Pulsar for TDC (G) Sensor
Tappet
Cam x 2
Q000768E
Operation Section
1– 13
(2) Exploded View
PCV
(Pump Control Valve)
Delivery Valve
Element
Cylinder Recognition Sensor
(TDC (G) Sensor)
Tappet
Cam
Roller
Camshaft
Priming Pump
Feed Pump
Q000769E
Operation Section
1– 14
(3) Supply Pump Component Part Functions
Component Parts
Functions
Feed Pump
Draws fuel from the fuel tank and feeds it to the pumping mechanism.
Overflow Valve
Regulates the pressure of the fuel in the supply pump.
PCV (Pump Control Valve)
Controls the quantity of fuel delivered to the rail.
Pumping
Cam
Actuates the tappet.
Mechanism
Tappet
Transmits reciprocating motion to the plunger.
Plunger
Moves reciprocally to draw and compress fuel.
Delivery Valve
Stops the reverse flow of fuel pumped to the rail.
Cylinder Recognition Sensor {TDC (G) Identifies the engine cylinders.
Sensor}
Feed Pump
• The feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the pump chamber
via the fuel filter. There are two types of feed pumps, the trochoid type and the vane type.
Trochoid Type
- The camshaft actuates the outer/inner rotors of the feed pump, causing them to start rotating. In accordance with
the space produced by the movement of the outer/inner rotors, the feed pump draws fuel into the suction port and
pumps fuel out the discharge port.
Outer Rotor
Suction Port
To Pump Chamber
Discharge Port
Inner Rotor
From Fuel Tank
Q000770E
Vane Type
- The camshaft actuates the feed pump rotor and the vanes slide along the inner circumference of the eccentric ring.
Along with the rotation of the rotor, the pump draws fuel from the fuel tank, and discharges it to the SCV and the
pumping mechanism.
Discharge Port
Rotor
Suction Port
Eccentric Ring
Vane
Q000771E
Operation Section
1– 15
PCV: Pump Control Valve
• The PCV (Pump Control Valve) regulates the fuel discharge quantity from the supply pump in order to regulate the
rail pressure. The fuel quantity discharged from the supply pump to the rail is determined by the timing with which the
current is applied to the PCV.
Actuation Circuit
- The diagram below shows the actuation circuit of the PCV. The ignition switch turns the PCV relay ON and OFF to
apply current to the PCV. The ECU handles ON/OFF control of the PCV. Based on the signals from each sensor,
it determines the target discharge quantity required to provide optimum rail pressure and controls the ON/OFF timing for the PCV to achieve this target discharge quantity.
From PCV relay
PCV
To Rail
PCV Relay
Ignition Switch
+B
PCV1
PCV2
Q000772E
Pumping Mechanism
• The camshaft is actuated by the engine and the cam actuates the plunger via the tappet to pump the fuel sent by the
feed pump. The PCV controls the discharge quantity. The fuel is pumped from the feed pump to the cylinder, and then
to the delivery valve.
PCV (Pump Control Valve)
Delivery Valve
To Rail
Plunger
Camshaft
Feed Pump
Pulsar for TDC (G) Sensor
Cam (3 Lobes: 6-Cylinders)
Q000773E
1– 16
Operation Section
CYLINDER RECOGNITION SENSOR {TDC (G) SENSOR}
• The cylinder recognition sensor {TDC (G) sensor} uses the alternating current voltage generated by the change in the
lines of magnetic force passing through the coil to send the output voltage to the ECU. This is the same for the engine
speed sensor installed on the engine side. A disc-shaped gear, which is provided in the center of the supply pump
camshaft, has cutouts that are placed at 120? intervals, plus an extra cutout. Therefore, this gear outputs seven pulses for every two revolutions of the engine (for a six-cylinder engine). Through the combination of engine-side engine
speed pulses and TDC pulses, the pulse after the extra cutout pulse is recognized as the No. 1 cylinder.
· For a 6-Cylinder Engine (Reference)
Cylinder Recognition Sensor
(TDC (G) Sensor)
No.1 Cylinder TDC (G) Pulse
· TDC (G) Pulse
No.6 Cylinder TDC (G) Standard Pulse
No.1 Cylinder Recognition TDC (G) Pulse
· Engine Speed Pulse
0 2 4 6 8 101214 0 2 4 6 810 1214 0 2 4 6 8 1012
No.1 Cylinder Engine Speed Standard Pulse
0 2 4 6 8 101214 0 2 4 6 8 101214 0 2 4 6 8 1012
No.6 Cylinder Engine Speed Standard Pulse
0 2 4 6 8
Q000774E
Operation Section
1– 17
(4) Supply Pump Operation
Supply Pump Overall Fuel Flow
• The fuel is drawn by the feed pump from the fuel tank and sent to the pumping mechanism via the PCV. The PCV
adjusts the quantity of fuel pumped by the pumping mechanism to the necessary discharge quantity, and the fuel is
pumped to the rail via the delivery valve.
Fuel Discharge Quantity Control
• The fuel sent from the feed pump is pumped by the plunger. In order to adjust the rail pressure, the PCV controls the
discharge quantity. Actual operation is as follows.
PCV and Plunger Operation During Each Stroke
Intake Stroke (A)
In the plunger's descent stroke, the PCV opens and low-pressure fuel is suctioned into the
plunger chamber via the PCV.
Pre-Stroke (B)
Even when the plunger enters its ascent stroke, the PCV remains open while it is not energized.
During this time, fuel drawn in through the PCV is returned through the PCV without being pressurized (pre-stroke).
Pumping Stroke (C)
At a timing suited to the required discharge quantity, power is supplied to close the PCV, the
return passage closes, and pressure in the plunger chamber rises. Therefore, the fuel passes
through the delivery valve (reverse cut-off valve) and is pumped to the rail. Specifically, the
plunger lift portion after the PCV closes becomes the discharge quantity, and by varying the timing for the PCV closing (the end point of the plunger pre-stroke), the discharge quantity is varied
to control the rail pressure.
Intake Stroke (A)
When the cam exceeds the maximum lift, the plunger enters its descent stroke and pressure in
the plunger chamber decreases. At this time, the delivery valve closes and fuel pumping stops. In
addition, the PCV opens because it is de-energized, and low-pressure fuel is suctioned into the
plunger chamber. Specifically, the system goes into state A.
Intake Stroke
Discharge Quantity
Q=
Pumping Stroke
d 2 (H-h)
4
Cam Lift
h
H
Pre-Stroke
Open Valve
PCV Operation
Close Valve
When Discharge When Discharge
Quantity Increases Quantity Decreases
Pumping the Required
Discharge Quantity
Pump Operation
PCV
Return
From Fuel Tank
To Rail
Pumping
Mechanism
Delivery Valve
Plunger
d
(A)
(B)
(C)
(A')
Q000775E
1– 18
Operation Section
3.2 HP2 Type
(1) Construction and Characteristics
• The supply pump is primarily composed of the two pumping mechanism (inner cam, roller, two plungers) systems,
the SCV (Suction Control Valve), the fuel temperature sensor, and the feed pump (vane type), and is actuated with
half the engine rotation.
• The pumping mechanism consists of an inner cam and a plunger, and forms a tandem configuration in which two systems are arranged axially. This makes the supply pump compact and reduces the peak torque.
• The quantity of fuel discharged to the rail is controlled by the fuel suction quantity using SCV (Suction Control Valve)
control. In order to control the discharge quantity with the suction quantity, excess pumping operations are eliminated,
reducing the actuation load and suppressing the rise in fuel temperature.
Fuel Temperature Sensor
Delivery Valve
Overflow
SCV
(Suction Control
Valve)
Fuel Suction (From Fuel Tank)
Regulating Valve
Feed Pump
Check Valve
Roller
Plunger
Inner Cam
Q000818E
Operation Section
1– 19
(2) Supply Pump Actuating Torque
• Because the pumping mechanism is a tandem configuration, its peak actuating torque is one-half that of a single
pump with the same discharge capacity.
Tandem Type
Single Type
Pumping
Pumping
Plunger 1
Composition
Plunger 2
Feed
Pumping
Suction
Torque (Oil Pumping Rate)
Torque (Oil Pumping Rate)
Torque Pattern
Feed
Pumping
Solid Line : Plunger 1
Broken Line: Plunger 2
Q000819E
1– 20
Operation Section
(3) Exploded View
Regulating Valve
Fuel Temperature Sensor
Camshaft
Inner Cam
Roller
Pump Body
Feed Pump
Shoe
Delivery Valve
SCV (Suction Control Valve)
Check Valve
Q000820E
Operation Section
1– 21
(4) Component Part Functions
Component Parts
Functions
Feed Pump
Draws fuel from the fuel tank and feeds it to the pumping mechanism.
Regulating Valve
Regulates internal fuel pressure in the supply pump.
SCV (Suction Control Valve)
Controls the quantity of fuel that is fed to the plunger in order to control fuel
pressure in the rail.
Pumping
Inner Cam
Actuates the plunger.
Mechanism
Roller
Actuates the plunger.
Plunger
Moves reciprocally to draw and compress fuel.
Delivery Valve
Maintains high pressure by separating the pressurized area (rail) from the
pumping mechanism.
Fuel Temperature Sensor
Detects the fuel temperature.
Check Valve
Prevents the pressurized fuel in the pumping mechanism from flowing back
into the suction side.
Feed Pump
• The feed pump is a four-vaned type that draws fuel from the fuel tank and discharges it to the pumping mechanism.
The rotation of the drive shaft causes the feed pump rotor to rotate and the vane to move by sliding along the inner
surface of the casing (eccentric ring). Along with the rotation of the rotor, the pump draws fuel from the fuel tank, and
discharges it to the SCV and the pumping mechanism. To keep the vane pressed against the inner circumference, a
spring is provided inside each vane, in order to minimize fuel leakage within the pump.
Eccentric Ring
Spring
Rotor
Vane
Front Cover
Rear Cover
Q000821E
Regulating Valve
• The purpose of the regulating valve is to control the feed pressure (fuel pumping pressure) sending fuel to the pumping mechanism. As the rotational movement of the pump increases and the feed pressure exceeds the pressure set
at the regulating valve, the valve opens by overcoming the spring force, allowing the fuel to return to the suction side.
Suction Inlet
Regulating Valve Body
Filter
Spring
Piston
Feed Pump
(Discharge Side)
Feed Pump
(Suction Side)
Regulating Valve
Open Valve Pressure Characteristic
Feed Pressure
(Pumping Pressure)
Regulating Valve
Open Valve
Pressure High
Open Valve
Pressure Low
Speed
Bushing
Q000822E
1– 22
Operation Section
SCV: Suction Control Valve
• A solenoid type valve has been adopted. The ECU controls the duration of the current applied to the SCV in order to
control the quantity of fuel drawn into the pumping mechanism. Because only the quantity of fuel required to achieve
the target rail pressure is drawn in, the actuating load of the supply pump decreases, thus improving fuel economy.
Stopper
Coil
Needle Valve
Spring
Q000823E
SCV ON
- When current is applied to the coil, it pulls the needle valve upward, allowing fuel to be drawn into the pumping
mechanism of the supply pump.
To Pump Pumping Mechanism
From Feed Pump
Q000824E
SCV OFF
- When current is no longer applied to the coil, the needle valve closes and stops the suction of fuel.
From Feed Pump
Q000825E
Operation Section
1– 23
Pumping Mechanism (Plunger, Inner Cam, Roller)
• The pumping mechanism is made up of the plunger, inner cam, and roller, and it draws in the fuel discharged by the
feed pump and pumps it to the rail. Because the drive shaft and the inner cam have an integral construction, the rotation of the drive shaft directly becomes the rotation of the inner cam.
• Two plunger systems are arranged in series (tandem type) inside the inner cam. Plunger 1 is situated horizontally,
and plunger 2 is situated vertically. Plunger 1 and plunger 2 have their suction and compression strokes reversed
(when one is on the intake, the other is discharging), and each plunger discharges twice for each one rotation, so for
one rotation of the supply pump, they discharge a total of four times to the rail.
Plunger 1
(Horizontal)
Plunger 2
(Vertical)
Plunger Length Combination
· Plunger 1: Medium + Medium
· Plunger 2: Short + Long
Roller
Roller Diameter: 9
Roller Length: 21mm
Material: Reinforced Ceramic
Inner Cam
(Cam Lift: 3.4mm)
Plunger 1
Cam 90 Rotation
Plunger 2
Plunger 1: Start of Suction
Plunger 2: Start of Pumping
Plunger 1: Start of Pumping
Plunger 2: Start of Suction
Q000826E
Delivery Valve
• The delivery valve, which contains two valve balls, delivers the pressurized fuel from plungers 1 and 2 to the rail in
alternating strokes. When the pressure in the plunger exceeds the pressure in the rail, the valve opens to discharge
fuel.
From Plunger 1
To Rail
From Plunger 2
Pin
Gasket
· When Plunger 1 Pumping
Guide
Stopper
Valve Ball
Holder
· When Plunger 2 Pumping
Q000827E
Operation Section
Fuel Temperature Sensor
• The fuel temperature sensor is installed on the fuel intake side and utilizes the characteristics of a thermistor in which
the electric resistance changes with the temperature in order to detect the fuel temperature.
Thermistor
Resistance Value
1– 24
Resistance - Temperature
Characteristic
Temperature
Q000828E
Check Valve
• The check valve, which is located between the SCV (Suction Control Valve) and the pumping mechanism, prevents
the pressurized fuel in the pumping mechanism from flowing back into the SCV.
Pump Housing
Spring
Valve
To Pumping Mechanism
Stopper
To SCV
Plug
Q000829E
Check Valve Open
- During fuel suction (SCV ON), the feed pressure opens the valve, allowing fuel to be drawn into the pumping mechanism.
To Pumping Mechanism
From SCV
Q000830E
Check Valve Closed
- During fuel pumping (SCV OFF), the pressurized fuel in the pumping mechanism closes the valve, preventing fuel
from flowing back into the SCV.
From Pumping Mechanism
Q000831E
Operation Section
1– 25
(5) Supply Pump Operation
Supply Pump Overall Fuel Flow
• Fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts
the fuel pressure to below a certain level. Fuel sent to the feed pump has the required discharge quantity adjusted by
the SCV and enters the pumping mechanism through the check valve. The fuel pumped by the pumping mechanism
is pumped through the delivery valve to the rail.
Overflow Orifice
Regulating Valve
To Tank
From Fuel Tank
Delivery Valve
To Rail
Cam
SCV1
Check Valve 1
Check Valve 2
Head
SCV2
Feed Pump
Plunger
Q000832E
Operation Section
1– 26
Fuel Discharge Quantity Control
• The diagram below shows that the suction starting timing (SCV (Suction Control Valve) ON) is constant (determined
by the pump speed) due to the crankshaft position sensor signal. For this reason, the fuel suction quantity is controlled
by changing the suction ending timing (SCV OFF). Hence, the suction quantity decreases when the SCV is turned
OFF early and the quantity increases when the SCV is turned OFF late.
• During the intake stroke, the plunger receives the fuel feed pressure and descends along the cam surface. When the
SCV turns OFF (suction end), the feed pressure on the plunger ends and the descent stops. Since the suction quantity
varies, when suction ends (except for maximum suction) the roller separates from the cam surface.
• When the drive shaft rotates and the cam peak rises and the roller comes in contact with the cam surface again, the
plunger is pressed by the cam and starts pumping. Since the suction quantity = the discharge quantity, the discharge
quantity is controlled by the timing with which the SCV is switched OFF (suction quantity).
360 CR
Crankshaft
Angle
TDC #3
TDC #1
Compression
Top Dead Center
TDC #2
TDC #4
Cylinder Recognition
Sensor Signal
0 2 4 6 8 101214 16 0 2 4 6 8 101214
Crankshaft Position
Sensor Signal
SCV 1
ON
OFF
SCV 2
ON
OFF
Suction
Suction
0 2 4 6 8 101214 16 0 2 4 6 8 101214
Increased Suction
Quantity
Suction
Decreased Suction Suction
Quantity
Delivery Valve
Discharge
Horizontal
Cam Lift
Pumping Suction
Pumping Suction
Vertical
Cam Lift
Pumping Suction
Fuel
Fuel
SCV
ON
Check Valve
Pumping Suction
OFF
OFF
OFF
Fuel
Plunger
Delivery Valve
Roller
Suction
Start of Suction
End of Suction
Pumping
Start of Pumping
End of Pumping
Q000833E
Operation Section
1– 27
3.3 HP3 Type
(1) Construction and Characteristics
• The supply pump is primarily composed of the pump unit (eccentric cam, ring cam, two plungers), the SCV (suction
control valve), the fuel temperature sensor and the feed pump (trochoid type), and is actuated at 1/1 or 1/2 the engine
rotation.
• The two compact pump unit plungers are positioned symmetrically above and below on the outside of the ring cam.
• The fuel discharge quantity is controlled by the SCV, the same as for the HP2, in order to reduce the actuating load
and suppress the rise in fuel temperature. In addition, there are two types of HP3 SCV: the normally open type (the
suction valve opens when not energized) and the normally closed type (the suction valve is closed when not energized).
• With a DPNR system (Diesel Particulate NOx Reduction) system, there is also a flow damper. The purpose of this
flow damper is to automatically shut off the fuel if a leak occurs in the fuel addition valve passage within the DPNR.
Suction Valve
Plunger
Feed Pump
Ring Cam
SCV (Suction Control Valve)
Fuel Temperature Sensor
Delivery Valve
Q000835E
1– 28
Operation Section
(2) Exploded View
Delivery Valve
Element Sub-Assembly
Delivery Valve
Fuel Temperature Sensor
Plunger
Feed Pump
Regulating Valve
SCV
(Suction Control Valve)
Ring Cam
Pump Housing
Plunger
Eccentric Cam
Camshaft
Delivery Valve
Element Sub-Assembly
Q000836E
Operation Section
1– 29
(3) Component Part Functions
Component Parts
Functions
Feed Pump
Draws fuel from the fuel tank and feeds it to the plunger.
Regulating Valve
Regulates the pressure of the fuel in the supply pump.
SCV (Suction Control Valve)
Controls the quantity of fuel that is fed to the plungers.
Pump Unit
Eccentric Cam
Actuates the ring cam.
Ring Cam
Actuates the plunger.
Plunger
Moves reciprocally to draw and compress fuel.
Delivery Valve
Prevents reverse flow from the rail of the fuel pumped from the plunger.
Fuel Temperature Sensor
Detects the fuel temperature.
Feed Pump
• The trochoid type feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the
two plungers via the fuel filter and the SCV (Suction Control Valve). The drive shaft actuates the outer/inner rotors of
the feed pump, thus causing the rotors to start rotating. In accordance with the space that increases and decreases
with the movement of the outer and inner rotors, the feed pump draws fuel into the suction port and pumps fuel out
the discharge port.
Outer Rotor
To Pump Chamber
Discharge Port
Suction Port
Inner Rotor
From Fuel Tank
Q000770E
Regulating Valve
• The regulating valve keeps the fuel feed pressure (discharge pressure) below a certain level. If the pump speed increases and the feed pressure exceeds the preset pressure of the regulating valve, the valve opens by overcoming
the spring force in order to return the fuel to the suction side.
Pump Housing
Bushing
Piston
Feed Pump
Spring
SCV
Plug
Q000837E
1– 30
Operation Section
Suction Control Valve (SCV)
• In contrast to the HP2, the SCV for the HP3 supply pump is equipped with a linear solenoid valve. The fuel flow volume supplied to the high-pressure plunger is controlled by adjusting the engine ECU supplies power to the SCV (duty
ratio control). When current flows to the SCV, the internal armature moves according to the duty ratio. The armature
moves the needle valve, controlling the fuel flow volume according to the amount that the valve body fuel path is
blocked. Control is performed so that the supply pump suctions only the necessary fuel quantity to achieve the target
rail pressure. As a result, the supply pump actuation load is reduced.
• There are two types of HP3 SCV: the normally open type (the suction valve opens when not energized) and the normally closed type (the suction valve is closed when not energized). The operation of each type is the reverse of that
of the other.
• In recent years, a compact SCV has been developed. Compared to the conventional SCV, the position of the return
spring and needle valve in the compact SCV are reversed. For this reason, operation is also reversed.
Normally Open Type
- When the solenoid is not energized, the return spring pushes against the needle valve, completely opening the fuel
passage and supplying fuel to the plungers. (Total quantity suctioned → Total quantity discharged)
- When the solenoid is energized, the armature pushes the needle valve, which compresses the return spring and
closes the fuel passage. In contrast, the needle valve in the compact SCV is pulled upon, which compresses the
return spring and closes the fuel passage.
- The solenoid ON/OFF is actuated by duty ratio control. Fuel is supplied in an amount corresponding to the open
surface area of the passage, which depends on the duty ratio, and then is discharged by the plungers.
Return Spring
Conventional SCV
External View
Solenoid
Valve Body
Needle Valve
Cross Section
Q002340E
Solenoid
Compact SCV
Valve Body
Return Spring
Needle Valve
External View
Cross Section
Q002309E
Operation Section
1– 31
Duty Ratio Control
- The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective
(average) value of these signals. As the effective value increases, the valve opening decreases, and as the effective value decreases, the valve opening increases.
High Suction Quantity
ON
OFF
Current
Actuating Voltage
Low Suction Quantity
Average Current Difference
QD0710E
When the SCV Energized Duration (Duty ON Time) is Short
- When the SCV energization time is short, the average current flowing through the solenoid is small. As a result, the
needle valve is returned by spring force, creating a large valve opening. Subsequently, the fuel suction quantity
increases.
Conventional SCV
Feed Pump
Large Valve
Opening
SCV
Needle
Valve
Q002341E
1– 32
Operation Section
Compact SCV
Feed Pump
Needle Valve
Large
Opening
Q002321E
When the SCV Energized Duration (Duty ON Time) is Long
- When the energization time is long, the average current flowing to the solenoid is large. As a result, the needle
valve is pressed out (in the compact SCV, the needle valve is pulled), creating a small valve opening. Subsequently,
the fuel suction quantity decreases.
Conventional SCV
Feed Pump
Small
Opening
SCV
Needle
Valve
Q002342E
Operation Section
1– 33
Compact SCV
Feed Pump
Needle Valve
SCV
Small Valve
Opening
Q002322E
Operation Section
1– 34
Normally Closed Type
- When the solenoid is energized, the needle valve is pressed upon (in the compact SCV, the cylinder is pulled upon)
by the armature, completely opening the fuel passage and supplying fuel to the plunger. (Total quantity suctioned
→ Total quantity discharged)
- When power is removed from the solenoid, the return spring presses the needle valve back to the original position,
closing the fuel passage.
- The solenoid ON/OFF is actuated by duty ratio control. Fuel is supplied in an amount corresponding to the open
surface area of the passage, which depends on the duty ratio, and then is discharged by the plungers.
Return Spring
Conventional SCV
Needle Valve
External View
Solenoid
Valve Body
Cross Section
Valve Body
Compact SCV
Q002343E
Solenoid
Return Spring
Needle Valve
External View
Cross Section
Q002323E
Duty Ratio Control
- The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective
(average) value of these signals. As the effective value increases, the valve opening increases, and as the effective
value decreases, the valve opening decreases.
Current
Actuating Voltage
High Suction Quantity
Low Suction Quantity
ON
OFF
Average Current Difference
Q000844E
Operation Section
1– 35
When the SCV Energized Duration (Duty ON Time) is Long
- When the energization time is long, the average current flowing to the solenoid is large. As a result, the needle
valve is pushed out (in the compact SCV, the needle valve is pulled), creating a large valve opening. Subsequently,
the fuel suction quantity increases.
Conventional SCV
Feed Pump
Needle
Valve
SCV
Large
Opening
Q002344E
Compact SCV
SCV
Feed Pump
Large Valve
Opening
Needle
Valve
Q002324 E
1– 36
Operation Section
When the SCV Energized Duration (Duty ON Time) is Short
- When the energization time is short, the average current flowing through the solenoid is small. As a result, the needle valve is returned to the original position by spring force, creating a small valve opening. Subsequently, the fuel
suction quantity decreases.
Conventional SCV
Feed Pump
Needle
Valve
SCV
Small
Opening
Q002345E
Compact SCV
Feed Pump
Small Valve
Opening
SCV
Needle
Valve
Q002325E
Operation Section
1– 37
Pump Unit (Eccentric Cam, Ring Cam, Plunger)
• The eccentric cam is attached to the camshaft and the ring cam is installed on the eccentric cam. There are two plungers at positions symmetrical above and below the ring cam.
Ring Cam
Plunger A
Camshaft
Feed Pump
Eccentric Cam
Plunger B
Q000845E
• Because the rotation of the camshaft makes the eccentric cam rotate eccentrically, the ring cam follows this and
moves up and down, and this moves the two plungers reciprocally. (The ring cam itself does not rotate.)
Eccentric Cam
Ring Cam
Camshaft
Q000846E
1– 38
Operation Section
Delivery Valve
• The delivery valve for the HP3 has an integrated element and is made up of the check ball, spring, and holder. When
the pressure at the plunger exceeds the pressure in the rail, the check ball opens to discharge the fuel.
Element
Check Ball
Holder
Spring
Plunger
Q000847E
Fuel Temperature Sensor
• The fuel temperature sensor is installed on the fuel intake side and utilizes the characteristics of a thermistor in which
the electric resistance changes with the temperature in order to detect the fuel temperature.
Resistance - Temperature
Characteristic
Resistance Value
Thermistor
Temperature
Q000848E
Operation Section
1– 39
(4) Supply Pump Operation
Supply Pump Overall Fuel Flow
• The fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts
the fuel pressure to below a certain level. The fuel sent from the feed pump has the required discharge quantity adjusted by the SCV, and enters the pump unit through the suction valve. The fuel pumped by the pump unit is pumped
through the delivery valve to the rail.
Inject
Rail
Discharge Valve
From Pump
Suction Pressure
Feed Pressure
High Pressure
Return Pressure
Suction Valve
Plunger
Return Spring
To Rail
Return
Combustion Overflow
Regulating Valve
Filter
Camshaft
Feed Pump
Fuel Intake Port
Suction
Fuel Filter
(With Priming Pump)
Fuel Tank
Q000849E
1– 40
Operation Section
Operation
• The discharge quantity is controlled by SCV control, the same as for the HP2, however it differs from the HP2 in that
the valve opening is adjusted by duty ratio control.
• In the intake stroke, the spring makes the plunger follow the movement of the ring cam, so the plunger descends together with the ring cam. Thus, unlike the HP2, the plunger itself also suctions in fuel. When the suctioned fuel passes
through the SCV, the flow quantity is controlled to the required discharge quantity by the valve opening and enters
the pump main unit.
• The quantity of fuel adjusted by the SCV is pumped during the pumping stroke.
Suction Valve
Plunger A
Delivery Valve
Eccentric Cam
Ring Cam
SCV
Plunger B
Plunger A: End of Compression
Plunger A: Start of Suction
Plunger B: End of Suction
Plunger B: Start of Compression
Plunger A: Start of Compression
Plunger A: End of Suction
Plunger B: Start of Suction
Plunger B: End of Compression
QD0707E
Operation Section
1– 41
3.4 HP4 Type
(1) Construction and Characteristics
• The HP4 basic supply pump construction is the same as for the HP3. The composition is also the same as the HP3,
being made up of the pump unit (eccentric cam, ring cam, plunger), the SCV (suction control valve), the fuel temperature sensor, and the feed pump. The main difference is that there are three plungers.
• Because there are three plungers, they are positioned at intervals of 120? around the outside of the ring cam. In addition, the fuel delivery capacity is 1.5 times that of the HP3.
• The fuel discharge quantity is controlled by the SCV, the same as for the HP3.
SCV (Suction Control Valve)
Fuel Temperature Sensor
Delivery Valve
Feed Pump
Plunger
Eccentric Cam
Suction Valve
Q000850E
1– 42
Operation Section
(2) Exploded View
SCV
IN
Filter
Fuel Temperature Sensor
Feed Pump
Regulating Valve
OUT
Pump Body
Ring Cam
Camshaft
Q000457E
Operation Section
1– 43
(3) Component Part Functions
Component Parts
Functions
Feed Pump
Draws fuel from the fuel tank and feeds it to the plunger.
Regulating Valve
Regulates the pressure of the fuel in the supply pump.
SCV (Suction Control Valve)
Controls the quantity of fuel that is fed to the plungers.
Pump Unit
Eccentric Cam
Actuates the ring cam.
Ring Cam
Actuates the plunger.
Plunger
Moves reciprocally to draw and compress fuel.
Suction Valve
Prevents reverse flow of compressed fuel into the SCV.
Delivery Valve
Prevents reverse flow from the rail of the fuel pumped from the plunger.
Fuel Temperature Sensor
Detects the fuel temperature.
• The HP4 supply pump component parts and functions are basically the same as for the HP3. The explanations below
only cover those points on which the HP4 differs from the HP3. For other parts, see the appropriate item in the explanation of the HP3.
Pump Unit (Eccentric Cam, Ring Cam, Plunger)
• A triangular ring cam is installed on the eccentric cam on the drive shaft, and three plungers are installed to the ring
cam at intervals of 120°.
Plunger
Camshaft
Eccentric Cam
Ring Cam
Q000851E
1– 44
Operation Section
• Because the rotation of the camshaft makes the eccentric cam rotate eccentrically, the ring cam follows this and this
moves the three plungers reciprocally. (The ring cam itself does not rotate.)
Ring Cam
Plunger #1
Plunger #2
End of Pumping
Pumping
Eccentric Cam
Camshaft
Rotate 120 Clockwise
Camshaft
Camshaft
Rotate 120 Clockwise
Suction
Plunger #3
Pumping
Suction
Suction
End of Pumping
Camshaft
Rotate 120 Clockwise
End of Pumping
Pumping
D000852E
Operation Section
1– 45
(4) Supply Pump Operation
Supply Pump Overall Fuel Flow
• The fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts
the fuel pressure to below a certain level. The fuel sent from the feed pump has the required discharge quantity adjusted by the SCV, and enters the pump unit through the suction valve. The fuel pumped by the pump unit is pumped
through the delivery valve to the rail.
Feed Pump from Fuel Tank (Suction)
SCV from Feed Pump (Low Pressure)
Pump Unit from SCV (Low-Pressure Adjustment Complete)
From Pump Unit to Rail (High Pressure)
SCV
Camshaft
To Rail
From Fuel
Tank
Feed Pump
Ring Cam
Plunger
Delivery Valve
Suction Valve
Q000853E
Operation
• The discharge quantity is controlled by the SCV. As with the HP3, the valve opening is adjusted by duty ratio control.
The only difference from the HP3 is the shape of the pump unit. Operation and control are basically the same. For
details on operation and control, see the explanation of the HP3.
Operation Section
1– 46
4. RAIL DESCCRIPTION
4.1 Rail Functions and Composition
z The function of the rail is to distribute fuel pressurized by the supply pump to each cylinder injector.
z The shape of the rail depends on the model and the component parts vary accordingly.
z The component parts are the rail pressure sensor (Pc sensor), pressure limiter, and for some models a flow damper and
pressure discharge valve.
Pressure Limiter
Flow Damper
Rail
Rail Pressure Sensor (Pc Sensor)
Pressure Discharge Valve
Rail
Pressure Limiter
Rail Pressure Sensor (Pc Sensor)
Q000854E
4.2 Component Part Construction and Operation
Component Parts
Rail
Functions
Stores pressurized fuel that has been pumped from the supply pump and distributes the fuel to each cylinder injector.
Pressure Limiter
Opens the valve to release pressure if the pressure in the rail becomes abnormally
high.
Rail Pressure Sensor (Pc Sensor)
Detects the fuel pressure in the rail.
Flow Damper
Reduces the pressure pulsations of fuel in the rail. If fuel flows out excessively, the
damper closes the fuel passage to prevent further flow of fuel. Mostly used with
engines for large vehicles.
Pressure Discharge Valve
Controls the fuel pressure in the rail. Mostly used with engines for passenger cars.
Operation Section
1– 47
(1) Pressure Limiter
• The pressure limiter opens to release the pressure if abnormally high pressure is generated. If pressure within the rail
becomes abnormally high, the pressure limiter operates (opens). It resumes operation (closes) after the pressure falls
to a certain level. Fuel released by the pressure limiter returns to the fuel tank.
< NOTE >
The operating pressures for the pressure limiter depend on the vehicle model and are approximately 140-230MPa for
the valve opening pressure, and approximately 30-50MPa for the valve closing pressure.
Leak
(To Fuel Tank)
Pressure Limiter
Abnormally High Pressure
Valve Open
Valve Close
Return
Rail Pressure
Q000855E
(2) Rail Pressure Sensor (Pc Sensor)
• The rail pressure sensor (Pc sensor) is installed on the rail. It detects the fuel pressure in the rail and sends a signal
to the engine ECU. This is a semi-conductor sensor that uses the piezo-electric effect of the electrical resistance varying when pressure is applied to a silicon element.
Output - Common Rail
Voltage Pressure Characteristic
Sensor Wiring Diagram
Pc
Vout
Vout
ECU
GND
GND
Vout
Vcc=5V
+5V
Output Voltage
Vcc
Vcc
Rail Pressure
Q000856E
• There are also rail pressure sensors that have dual systems to provide a backup in case of breakdown. The output
Pc
Sensors
VC
VCS
+5V
Vout/Vcc
PR
PR2
ECU
ECU
E2
E2S
VC
PR
E2
Vcc=5V
Output Voltage 2
E2S PR2 VCS
Output Voltage 1
voltage is offset.
Rail Pressure
Q000857E
1– 48
Operation Section
(3) Flow Damper
• The flow damper reduces the pressure pulsations of the fuel in the pressurized pipe and supplies fuel to the injectors
at a stabilized pressure. The flow damper also presents abnormal discharge of fuel by shutting off the fuel passage
in the event of excess fuel discharge, for example due to fuel leaking from an injection pipe or injector. Some flow
dampers combine a piston and ball, and some have only a piston.
Type Combining Piston and Ball
Piston
Ball
Seat
Piston-Only Type
Piston
Seat
Spring
Spring
Q000858E
Operation of Piston-and-Ball Type
- When a pressure pulse occurs in a high-pressure pipe, the resistance of it passing through the orifice disrupts the
balance between the rail side and injector side pressures, so the piston and ball move to the injector side, absorbing
the pressure pulse. With normal pressure pulses, since the rail side and injector side pressures are soon balanced,
the piston and ball are pushed back to the rail side by the spring. If there is an abnormal discharge, for example
due to an injector side fuel leak, the amount of fuel passing through the orifice cannot be balanced out and the piston presses the ball against the seat, so the passage for fuel to the injector is shut off.
· During Pressure Pulse Absorption
Piston
· Fuel Cut-Off
Ball
Spring
Seat
Q000859E
Operation of Piston-Only Type
- The piston contacts the seat directly and the piston shuts off the fuel passage directly. Operation is the same as for
the piston-and-ball type.
· During Pressure Pulse Absorption
Piston
· Fuel Cut-Off
Seat
Spring
Q000860E
Operation Section
1– 49
(4) Pressure Discharge Valve
• The pressure discharge valve controls the fuel pressure in the rail. When rail fuel pressure exceeds the target injection
pressure, or when the engine ECU judges that rail fuel pressure exceeds the target value, the pressure discharge
valve solenoid coil is energized. This opens the pressure discharge valve passage, allowing fuel to leak back to the
fuel tank, and reducing rail fuel pressure to the target pressure.
Solenoid Coil
Pressure Discharge Valve
Rail
Operating
ON
ECU
To Fuel tank
Q000861E
1– 50
Operation Section
5. INJECTOR DESCRIPTION
5.1 General Description
z The injector injects the pressurized fuel in the rail into the engine combustion chamber at the optimal injection timing,
injection quantity, injection rate, and injection pattern, in accordance with signals from the ECU.
z Injection is controlled using a TWV (Two-Way Valve) and orifice. The TWV controls the pressure in the control chamber
to control the start and end of injection. The orifice controls the injection rate by restraining the speed at which the nozzle
opens.
z The command piston opens and closes the valve by transmitting the control chamber pressure to the nozzle needle.
z When the nozzle needle valve is open, the nozzle atomizes the fuel and injects it.
z There are three types of injectors: the X1, X2, and G2.
TWV
Rail Pressure Sensor
Orifice
ECU
Control Chamber Portion
Rail
Command Piston
Supply Pump
Nozzle Needle
Nozzle
Q000862E
Operation Section
1– 51
5.2 Injector Construction and Features
z The injector consists of a nozzle similar to the conventional "nozzle & nozzle holder", an orifice that controls the injection
rate, the command piston, and a TWV (two-way solenoid valve). The basic construction is the same for the X1, X2, and
G2 types.
(1) X1 Type
• Precision control is attained through electronic control of the injection. The TWV comprises two valves: the inner valve
(fixed) and the outer valve (movable).
Solenoid
TWV
Inner Valve
Outer Valve
Command Piston
Orifice 1
Orifice 2
Nozzle
Q000863E
1– 52
Operation Section
(2) X2 Type
• By reducing the injector actuation load, the injector has been made more compact and energy efficient, and its injection precision has been improved. The TWV directly opens and closes the outlet orifice.
Hollow Screw with Damper
Solenoid
Valve
Control
Chamber
From Rail
O-ring
Command Piston
Nozzle Spring
Pressure Pin
Seat
Leak Passage
High-Pressure Fuel
Nozzle Needle
Q000864E
Operation Section
1– 53
(3) G2 Type
• To ensure high pressure, the G2 type has improved pressure strength, sealing performance and pressure wear resistance. It also has improved high-speed operability, enabling higher-precision injection control and multi-injection.
To Fuel Tank
Connector
Solenoid Valve
From Rail
Command Piston
Nozzle Spring
Pressure Pin
Nozzle Needle
Leak Passage
Seat
Q000865E
< NOTE >
Multi-injection means that for the purpose of reducing exhaust gas emissions and noise, the main injection is accomplished with one to five injections of fuel without changing the injection quantity.
Injection Quantity
Example : Pattern with Five Injections
Main Injection
After-Injection
Pilot Injection Pre-Injection
Time
Post-Injection
Q000866E
Operation Section
1– 54
5.3 Injector Operation
z The injector controls injection through the fuel pressure in the control chamber. The TWV executes leak control of the
fuel in the control chamber to control the fuel pressure within the control chamber. The TWV varies with the injector type.
Non-Injection
• When the TWV is not energized, the TWV shuts off the leak passage from the control chamber, so the fuel pressure
in the control chamber and the fuel pressure applied to the nozzle needle are both the same rail pressure. The nozzle
needle thus closes due to the difference between the pressure-bearing surface area of the command piston and the
force of the nozzle spring, and fuel is not injected. For the X1 type, the leak passage from the control chamber is shut
off by the outer valve being pressed against the seat by the force of the spring, and the fuel pressure within the outer
valve. For the X2/G2 types, the control chamber outlet orifice is closed directly by the force of the spring.
Injection
• When TWV energization starts, the TWV valve is pulled up, opening the leak passage from the control chamber.
When this leak passage opens, the fuel in the control chamber leaks out and the pressure drops. Because of the drop
in pressure within the control chamber, the pressure on the nozzle needle overcomes the force pressing down, the
nozzle needle is pushed up, and injection starts. When fuel leaks from the control chamber, the flow quantity is restricted by the orifice, so the nozzle opens gradually. The injection rate rises as the nozzle opens. As current continues
to be applied to the TWV, the nozzle needle eventually reaches the maximum amount of lift, which results in the maximum injection rate. Excess fuel is returned to the fuel tank through the path shown.
End of Injection
• When TWV energization ends, the valve descends, closing the leak passage from the control chamber. When the
leak passage closes, the fuel pressure within the control chamber instantly returns to the rail pressure, the nozzle
closes suddenly, and injection stops.
X2 · G2
Leak Passage
To Fuel Tank
Solenoid
TWV
X1
Actuating
Current
Inner
Valve
Actuating
Current
Outer Valve
Actuating
Current
TWV
Rail
Leak
Passage
Outlet Orifice
Control Outlet Orifice
Chamber
Pressure
Inlet Orifice
Control
Chamber
Pressure
Control
Chamber
Pressure
Command
Piston
Injection Rate
Injection Rate
Injection Rate
Nozzle
Non-Injection
Injection
End of Injection
Q000867E
Operation Section
1– 55
5.4 Injector Actuation Circuit
z In order to improve injector responsiveness, the actuation voltage has been changed to high voltage, speeding up both
solenoid magnetization and the response of the TWV. The EDU or the charge circuit in the ECU raises the respective
battery voltage to approximately 110V, which is supplied to the injector by signal from the ECU to actuate the injector.
EDU Actuation
EDU
Constant
Amperage Circuit
Charging Circuit
High Voltage
Generation Circuit
Injector
INJ#1 (No.1 Cylinder)
Actuating Current
IJt
INJ#2 (No.3 Cylinder)
ECU
INJ#3 (No.4 Cylinder)
Control
Circuit
IJf
INJ#4 (No.2 Cylinder)
ECU Direct Actuation
Common 2
Common 1
Injector
ECU
Constant
Amperage Circuit
Constant
Amperage Circuit
High Voltage Generation Circuit
2WV#1 (No.1 Cylinder)
Actuating Current
2WV#2 (No.5 Cylinder)
2WV#3 (No.3 Cylinder)
2WV#4 (No.6 Cylinder)
2WV#5 (No.2 Cylinder)
2WV#6 (No.4 Cylinder)
Q000868E
1– 56
Operation Section
5.5 Other Injector Component Parts
(1) Hollow Screw with Damper
• The hollow screw with damper enhances injection quantity accuracy, by reducing the back-pressure pulsations (pressure fluctuations) of the leak fuel. In addition, it minimizes the back-pressure dependence (the effect of the pressure
in the leak pipe changing the injection quantity even though the injection command is the same) of the fuel in the leak
pipe.
Hollow Screw with Damper
O-ring
Damper
O-ring
To Fuel tank
Q000869E
(2) Connector with Correction Resistor
• The connector with correction resistor has a built-in correction resistor in the connector section to minimize injection
quantity variation among the cylinders.
Correction Resistor Terminal
Solenoid Terminal
Q000870E
Operation Section
1– 57
(3) Injector with QR Codes
• QR (Quick Response) codes have been adopted to enhance correction precision. The QR code, which contains the
correction data of the injector, is written to the engine ECU. QR codes have resulted in a substantial increase in the
number of fuel injection quantity correction points, greatly improving injection quantity precision.
· QR Code Correction Points (Example)
10EA01EB
13EA01EB
0300 0000
0000 BC
ID Codes
Pressure
Parameter
Injection Quantity
QR Codes
Actuating Pulse Width TQ
Q000871E
< NOTE >
QR codes are a new two-dimensional code that was developed by DENSO. In addition to injection quantity correction
data, the code contains the part number and the product number, which can be read at extremely high speeds.
1– 58
Operation Section
Handling Injectors with QR Codes (Reference)
- Injectors with QR codes have the engine ECU recognize and correct the injectors, so when an injector or the engine
ECU is replaced, it is necessary to register the injector's ID code in the engine ECU.
Replacing the Injector
- It is necessary to register the ID code of the injector that has been replaced in the engine ECU.
"No correction resistance, so no electrical recognition capability."
Spare Injector
Engine ECU
* Necessary to record the injector ID codes in the Engine ECU.
QD1536E
Replacing the Engine ECU
- It is necessary to register the ID codes of all the vehicle injectors in the engine ECU.
"No correction resistance, so no electrical recognition capability."
Vehicle-Side Injector
Spare Engine ECU
* Necessary to record the injector ID codes in the Engine ECU.
Q000985E
Operation Section
1– 59
6. DESCRIPTION OF CONTROL SYSTEM COMPONENTS
6.1 Engine Control System Diagram (Reference)
Accelerator Position Sensor
Ignition Switch Signal
Starter Signal
Warm-Up Switch Signal
Vehicle Speed Signal
Supply Pump
PCV(HP0)
SCV(HP2·3·4)
TDC(G) Sensor
(HP0)
Engine ECU
Fuel Temperature
Sensor (HP2·3·4)
Charge
Circuit
EDU
Pressure Discharge Valve
Pressure Limiter
Rail
Flow Damper
(Large Vehicles)
Rail Pressure Sensor
Intake Air
Temperature
Sensor
Airflow Meter
(with Intake Air Temperature Sensor)
E-VRV for EGR
To Fuel Tank
Intake Air
Pressure Sensor
Fuel Temperature Sensor (HP0)
Injector
EGR Shut-Off VSV
Coolant Temperature Sensor
Cylinder Recognition Sensor
(TDC (G) Sensor: HP2, 3, 4)
Crankshaft Position Sensor
(Engine Speed Sensor)
Flywheel
Supply Pump
PCV
TDC (G) Sensor
Fuel Temperature Sensor
SCV
Fuel Temperature Sensor
SCV
SCV
Fuel Temperature Sensor
HP0
HP2
HP3
HP4
Q000874E
1– 60
Operation Section
6.2 Engine ECU (Electronic Control Unit)
z The engine ECU constantly ascertains the status of the engine through signals from the sensors, calculates fuel injection quantities etc. appropriate to the conditions, actuates the actuators, and controls to keep the engine in an optimal
state. The injectors are actuated by either the EDU or the charge circuit in the engine ECU. This actuation circuit depends on the specifications of the model it is mounted in. The ECU also has a diagnosis function for recording system
troubles.
Sensors
Engine ECU
Actuators
Actuation Circuit
EDU
or
Cylinder Recognition Sensor
(TDC (G) Sensor)
Injector
Charge Circuit
(Built into ECU)
Crankshaft Position Sensor
(Engine Speed Sensor)
Engine ECU
Supply Pump
(PCV : HP0, SCV : HP2 · HP3 · HP4)
Accelerator Position Sensor
Other Sensors
Other Actuators
Q000875E
6.3 EDU (Electronic Driving Unit)
(1) General Description
• An EDU is provided to enable high-speed actuation of the injectors. The EDU has a high-voltage generation device
(DC/DC converter) and supplies high voltage to the injectors to actuate the injectors at high speed.
Actuation Signal
Actuation Output
ECU
Check Signal
EDU
Q000876E
Operation Section
1– 61
(2) Operation
• The high-voltage generating device in the EDU converts the battery voltage into high voltage. The ECU sends signals
to terminals B through E of the EDU in accordance with the signals from the sensors. Upon receiving these signals,
the EDU outputs signals to the injectors from terminals H through K. At this time, terminal F outputs the IJf injection
verification signal to the ECU.
+B
COM
A
L
High Voltage
Generation Circuit
IJt#1
IJt#2
IJt#1
I
C
Control Circuit
IJt#3
ECU
H
B
J
D
IJt#4
IJt#2
IJt#3
K
E
IJt#4
IJf
F
G
M
GND
GND
Q000877E
6.4 Various Sensors
Various Sensor Functions
Sensor
Crankshaft
Position
Functions
Sensor Detects the crankshaft angle and outputs the engine speed signal.
(Engine Speed Sensor)
Cylinder
Recognition
Sensor Identifies the cylinders.
(TDC (G) Sensor)
Accelerator Position Sensor
Detects the opening angle of the accelerator pedal.
Intake Air Temperature Sensor
Detects the temperature of the intake air after it has passed through the turbocharger.
Mass Airflow Meter
Detects the flow rate of the intake air. It also contains an intake air temperature sensor that detects the temperature of the intake air (atmospheric temperature).
Coolant Temperature Sensor
Detects the engine coolant temperature.
Fuel Temperature Sensor
Detects the fuel temperature.
Intake Air Pressure Sensor
Detects the intake air pressure.
Atmospheric Pressure Sensor
Detects the atmospheric pressure.
1– 62
Operation Section
(1) Crankshaft Position Sensor (Engine Speed Sensor) and Cylinder Recognition Sensor
{TDC (G) Sensor}
Crankshaft Position Sensor (Engine Speed Sensor)
• The crankshaft position sensor is installed near the crankshaft timing gear or the flywheel. The sensor unit is a MPU
(magnetic pickup) type. When the engine speed pulsar gear installed on the crankshaft passes the sensor section,
the magnetic field of the coil within the sensor changes, generating AC voltage. This AC voltage is detected by the
engine ECU as the detection signal. The number of pulses for the engine speed pulsar depends on the specifications
of the vehicle the sensor is mounted in.
Cylinder Recognition Sensor {TDC (G) Sensor}
• The cylinder recognition sensor is installed on the supply pump unit for the HP0 system, but for the HP2, HP3, or HP4
system, it is installed near the supply pump timing gear. Sensor unit construction consists of the MPU type, which is
the same as for the crankshaft position sensor, and the MRE (magnetic resistance element) type. For the MRE type,
when the pulsar passes the sensor, the magnetic resistance changes and the voltage passing through the sensor
changes. This change in voltage is amplified by the internal IC circuit and output to the engine ECU. The number of
pulses for the TDC pulsar depends on the specifications of the vehicle the sensor is mounted in.
Sensor Mounting Position (Reference)
Cylinder Recognition Sensor
(TDC (G) Sensor)
Pulsar
(Gearless Section)
Pulsar
For MPU
Type
Engine Speed Pulsar
For MRE
Type
TDC (G) Pulsar
Crankshaft Position Sensor
(Engine Speed Sensor)
External View of Sensor
NEShielded
TDC(G)- TDC(G)
Wire
NE+
Circuit Diagram
VCC
GND
TDC(G)
MPU
Type
TDC(G)
Crankshaft Position Sensor
(Engine Speed Sensor)
TDC (G) Input Circuit
VCC
TDC(G)
GND
MRE
Type
MPU Type
ECU
NE
MRE Type
Engine Speed
Input Circuit
Cylinder Recognition Sensor
(TDC (G) Sensor)
Pulse Chart (Reference)
360 CA
360 CA
Engine Speed
Pulse
MPU
Type
TDC (G)
Pulse
MRE
Type
0V
720 CA
Q000878E
Operation Section
1– 63
(2) Accelerator Position Sensor
• The accelerator position sensor converts the accelerator opening into an electric signal and outputs it to the engine
ECU. There are two types of accelerator position sensor: the hall element type and the contact type. In addition, to
provide backup in the event of breakdown, there are two systems and the output voltage is offset.
Hall Element Type
- This sensor uses a hall element to generate voltage from change in the direction of the magnetic field. A magnet
is installed on the shaft that rotates linked with the accelerator pedal, and the rotation of this shaft changes the magnetic field of the Hall element. The voltage generated by this change in the magnetic field is amplified by an amplifier
and input to the engine ECU.
A-VCC
VACCP Output Voltage (V)
Amplifier No. 1
Magnets (Pair)
+5V
VACCP1
A-GND
A-VCC
+5V
VACCP2
A-GND
ECU
Accelerator Pedal
Amplifier No. 2
Hall Elements (2)
4
3
2
1
0
50
100
Accelerator Opening (%)
Q000879E
Contact Type
- The sensor uses a contact-type variable resistor. Since the lever moves linked with the accelerator pedal, the sensor resistance value varies with the accelerator pedal opening. Therefore, the voltage passing the sensor changes,
and this voltage is input to the engine ECU as the accelerator opening signal.
Accelerator Position Sensor
Accelerator Position Sensor Circuit Diagram
Fully Open
Fully
Closed
Fully Closed
Fully
Open
EP2 VPA2 VCP2 EP1 VPA1 VCP1
Output Voltage
Accelerator Position Sensor
Output Voltage Characteristic
VPA2
VPA1
Fully Closed Fully Open
Accelerator Pedal Position
Q000880E
1– 64
Operation Section
(3) Intake Air Temperature Sensor
• The intake air temperature sensor detects the temperature of the intake air after it has passed the turbocharger. The
sensor portion that detects the temperature contains a thermistor. The thermistor, which has an electrical resistance
that changes with temperature, is used to detect the intake air temperature.
Thermistor
Resistance
Resistance - Temperature
Characteristic
Temperature
Q000881E
(4) Mass Airflow Meter (with Built-In Intake Air Temperature Sensor)
• The mass air flow meter is installed behind the air cleaner and detects the intake air flow (mass flow). This sensor is
a hot-wire type. Since the electrical resistance of the hot wire varies with the temperature, this characteristic is utilized
to measure the intake air quantity. The mass airflow meter also has a built-in intake air temperature sensor (thermistor
type) and detects the intake air temperature (atmospheric temperature).
Intake Air
Temperature
Sensor
+B
E2G
VG THAF
Resistance
Intake Air Temperature
Temperature
Sensor Resistance
Characteristic
E2
Hot Wire
Temperature C ( F)
Q000882E
(5) Coolant Temperature Sensor
• The coolant temperature sensor is installed on the cylinder block and detects the coolant temperature. This sensor is
a thermistor type.
+5V
Thermistor
VTHW
A-GND
Resistance Value
ECU
Coolant Temperature Water Temperature
Sensor Resistance
Characteristic
Coolant Temperature
Q000883E
Operation Section
1– 65
(6) Fuel Temperature Sensor
• This is a thermistor type sensor that detects the fuel temperature. In the HP2, HP3, and HP4 systems, this sensor is
installed on the supply pump unit, but in the HP0 system, it is installed on a leak pipe from an injector.
Resistance - Temperature
Characteristic
Resistance Value
Thermistor
Temperature
Q000848E
(7) Intake Air Temperature Sensor and Atmospheric Pressure Sensor
• This sensor is a semiconductor type sensor. It measures pressure utilizing the piezoelectric effect that when the pressure on the silicon element in the sensor changes, its electrical resistance changes. In addition, the air pressure on
this sensor is switched between the pressure within the intake manifold and the atmospheric pressure, so both the
intake air pressure and the atmospheric pressure are detected with one sensor. The switching between intake air
pressure and atmospheric pressure is handled by the VSV (vacuum switching valve). When any one of the conditions
below is established, the VSV is switched ON for 150 msec. by command of the engine ECU to detect the atmospheric
pressure. When none of the conditions below is established, the VSV is switched OFF to detect the intake air pressure.
Atmospheric Pressure Measurement Conditions
- Engine speed = 0 rpm
- Starter ON
- Stable idling state
PIM Output Voltage PIM
E2
Output Voltage
VC
Pressure
Characteristic
Absolute Pressure
Q000885E
1– 66
Operation Section
7. CONTROL SYSTEM
7.1 Fuel Injection Control
(1) General Description
• This system effects more appropriate control of the fuel injection quantity and injection timing than the mechanical
governor or timer used in the conventional injection pump. The engine ECU performs the necessary calculations
based on the signals that are received from the sensors located on the engine and the vehicle. Then, the ECU controls
the timing and duration of the current that is applied to the injectors in order to obtain optimal injection timing and
injection quantity.
(2) Various Types of Fuel Injection Controls
Control
Fuel Injection Quantity Control
Functions
This control replaces the function of the governor in the conventional injection
pump. It achieves optimal injection quantity by effecting control in accordance with
the engine speed and accelerator opening signals.
Fuel Injection Timing Control
This control replaces the function of the timer in the conventional injection pump. It
achieves optimal injection timing by effecting control in accordance with the
engine speed and the injection quantity.
Fuel Injection Rate Control
This function controls the ratio of the fuel quantity that is injected from the orifice of
(Pilot Injection Control)
the injector within a given unit of time.
Fuel Injection Pressure Control
This control uses the rail pressure sensor to measure the fuel pressure, and it
feeds this data to the engine ECU in order to control the pump discharge quantity.
Operation Section
1– 67
(3) Fuel Injection Quantity Control
General Description
• This control determines the fuel injection quantity by adding coolant temperature, fuel temperature, intake air temperature, and intake air pressure corrections to the basic injection quantity. The engine ECU calculates the basic injection
quantity based on the engine operating conditions and driving conditions.
Injection Quantity Calculation Method
• The calculation consists of a comparison of the following two values: 1. The basic injection quantity that is obtained
from the governor pattern, which is calculated from the accelerator position and the engine speed. 2. The injection
quantity obtained by adding various types of corrections to the maximum injection quantity obtained from the engine
speed. The lesser of the two injection quantities is used as the basis for the final injection quantity.
Injection
Quantity
Accelerator Opening
Engine Speed
Accelerator Opening
Basic Injection Quantity
Engine Speed
Low
Quantity
Side Selected
Corrected
Final Injection
Quantity
Injector Actuation
Period Calculation
Maximum Injection Quantity
Individual Cylinder
Correction Quantity
Speed Correction
Injection
Quantity
Injection Pressure Correction
Intake Air Pressure Correction
Engine Speed
Intake Air Temperature Correction
Atmospheric Pressure Correction
Ambient Temperature Correction
Cold Engine Maximum Injection Quantity Correction
Q000887E
Operation Section
Set Injection Quantities
• Basic Injection Quantity
This quantity is determined by the engine speed and the accelerator opening. With the engine speed constant, if the
accelerator opening increases, the injection quantity increases; with the accelerator opening constant, if the engine
Basic Injection Quantity
speed rises, the injection quantity decreases.
Accelerator Opening
Engine Speed
Q000888E
• Starting Injection Quantity
This is determined based on the basic injection quantity for when the engine starts up and the added corrections for
the starter S/W ON time, the engine speed, and the coolant temperature. If the coolant temperature is low, the injection quantity is increased. When the engine has completely started up, this mode is cancelled.
Injection Quantity
Coolant Temperature
High
Low
Starting
Base Injection
Quantity
STA ON Time
STA ON
Starting
Q000889E
• Injection Quantity for Maximum Speed Setting
Determined by the engine speed. The injection quantity is restricted to prevent an excessive rise in engine speed
(overrun).
Injection Quantity
1– 68
Injection Quantity
for Maximum Speed Setting
Engine Speed
Q000890E
Operation Section
1– 69
• Maximum Injection Quantity
This is determined based on the basic maximum injection quantity determined by the engine speed, and the added
corrections for coolant temperature, fuel temperature, intake air temperature, atmospheric temperature, intake air
Basic Maximum
Injection Quantity
pressure, atmospheric pressure, and full Q adjustment resistance (only for the 1st generation HP0 system), etc.
Engine Speed
QB0717E
Corrections
• Cold Engine Maximum Injection Quantity Correction
When the coolant temperature is low, whether during start-up or during normal operation, this correction increases
Injection Quantity
the injection quantity.
Engine Speed
Q000891E
• Intake Air Pressure Correction
When the intake air pressure is low, the maximum injection quantity is restricted in order to reduce the emission of
Injection Quantity
black smoke.
Intake Air Pressure
Correction Quantity
Engine Speed
Q000892E
Operation Section
• Atmospheric Pressure Correction
The maximum injection quantity is increased and decreased according to the atmospheric pressure. When the atmo-
Injection Quantity
spheric pressure is high, the maximum injection quantity is increased.
Atmospheric Pressure
Correction Quantity
Engine Speed
Q000893E
• Injection Quantity Delay Correction for Acceleration
During acceleration, if there is a large change in the accelerator pedal opening, the injection quantity increase is delayed in order to prevent black smoke emissions.
Change in Accelerator
Pedal Position
Injection Quantity
Injection Quantity
After Correction
Delay
Time
Q000487E
• Full Q Adjustment Resistance (Only for 1st Generation HP0 Systems)
The full Q resistance is for correcting the injection quantity for a full load. The maximum injection quantity is increased
or decreased by the car manufacturer to match to standards. There are 15 types of full Q adjustment resistance. The
appropriate one is selected and used.
ECU
+5V
VLQC
A-GND
Quantity Adjustment
Correction Injection Quantity
1– 70
Quantity Adjustment
Resistor Correction Voltage
Operation Section
1– 71
(4) Fuel Injection Rate Control
• Although the injection rate increases with the adoption of high-pressure fuel injection, the ignition lag, which is the
delay from the start of injection to the beginning of combustion, cannot be shortened to less than a certain period of
time. Therefore, the quantity of fuel injected until ignition takes place increases (the initial injection rate is too high),
resulting in explosive combustion simultaneous with ignition, and an increase in NOx and sound. To counteract this
situation, pilot injection is provided to keep the initial injection at the minimum requirement rate, to dampen the primary
explosive combustion, and to reduce NOx and noise.
[Ordinary Injection]
[Pilot Injection]
Injection Rate
Small First-Stage
Combustion
Large First-Stage
Combustion
Heat Release Rate
-20
TDC
Crankshaft Angle (deg)
20
40
-20
TDC
20
40
Crankshaft Angle (deg)
Q000895E
1– 72
Operation Section
(5) Fuel Injection Timing Control
• The fuel injection timing is controlled by the timing of the current applied to the injectors. After the main injection period
is decided, the pilot injection and other injection timing is determined.
Main Injection Timing
- The basic injection timing is calculated from the engine speed (engine speed pulse) and the final injection quantity,
to which various types of corrections are added in order to determine the optimal main injection timing.
Pilot Injection Timing (Pilot Interval)
- Pilot injection timing is controlled by adding a pilot interval value to the main injection. The pilot interval is calculated
based on the final injection quantity, engine speed, coolant temperature, atmospheric temperature, and atmospheric pressure (map correction). The pilot interval at the time the engine is started is calculated from the coolant tem-
Pilot Interval
Basic Injection
Timing
Pilot Interval
Basic Injection Timing
perature and engine speed.
Engine Speed
Engine Speed
1. Outline of Injection Timing Control Timing
0
Engine Speed
Pulse
Actual Top Dead Center
1
NE
Pilot Injection
Injector Solenoid Valve
Control Pulse
INJ
Nozzle Needle
Lift
lift
Main Injection
Pilot Injection Timing
Main Injection Timing
Pilot Interval
2. Injection Timing Calculation Method
Engine Speed
Injection Quantity
Main
Injection Timing
Basic Injection
Timing
Correction
Pilot
Injection Timing
Battery Voltage Correction
Intake Air Pressure Correction
Intake Air Temperature Correction
Atmospheric Pressure Correction
Coolant Temperature Correction
Q000896E
Operation Section
1– 73
Split Injection
- The purpose of split injection is to improve the startability of a cold engine. Before the conventional main injection
takes place, this function injects two or more extremely small injections of fuel.
Main Injection
Main Injection
Pilot Injection
This is the same as conventional
fuel injection.
Pilot Injection
Before the main injection, a small
quantity of fuel is injected.
Pilot Injection
Pre-Injection
Multi-Injection
If the temperature is low when the engine
starts, a small quantity of fuel is injected
divided over multiple injections before the
main injection.
Q000897E
Multi-Injection Control (Only for Some Models)
- Multi-injection control is when small injections (up to four times) are carried out before and after the main injection
in accordance with the state of the main injection and engine operation. This interval (the time A-D in the diagram
below) is based on the final injection quantity, engine speed, coolant temperature, and atmospheric pressure (map
correction). The interval during start-up is based on the coolant temperature and engine speed.
TDC
TDC (G) Pulse
A
B
C
D
Injection Rate
Q000898E
(6) Fuel Injection Pressure Control
• The engine ECU calculates the fuel injection pressure, which is determined by the final injection quantity and the engine speed. The calculation is based on the coolant temperature and engine speed during start-up.
Rail Pressure
Final Injection Quantity
Engine Speed
Q000899E
1– 74
Operation Section
(7) Other Injection Quantity Control
Idle Speed Control (ISC) System
• The idle speed control system controls the idle speed by regulating the injection quantity in order to match the actual
speed to the target speed calculated by the computer. The ISC can be automatic ISC or manual ISC.
Automatic ISC
- With automatic ISC, the engine ECU sets the target speed. The target engine speed varies with the type of transmission (automatic or manual), whether the air conditioner is ON or OFF, the shift position, and the coolant temperature.
Idle Speed Control Conditions
Conditions When Control Starts
Conditions Affecting Control
· Idle Switch
· Water Temperature
· Accelerator Opening
· Air Conditioning Load
· Vehicle Speed
· Shift Position
Engine ECU
Target Engine Speed Calculation
Comparison
Actual Engine Speed
Fuel injection Quantity Correction
Fuel Injection Quantity Instruction
Actuators
Q000900E
Operation Section
1– 75
Manual ISC
- The idle engine speed is controlled by the setting on the idle setting button at the driver's seat.
ECU
A-VCC
Target Engine Speed
+5V
V-IMC
A-GND
IMC Volume Terminal Voltage
Q000901E
Idle Vibration Reduction Control
- This control reduces engine vibration during idle. To achieve smooth engine operation, it compares the angle
speeds (times) of the cylinders and regulates injection quantity for each individual cylinder in the event of a large
difference.
#1
#3
t1
#4
t3
(Make the
t4
t for all the cylinders equal.)
Angular Speed
#1
#3
#4
#2
Crankshaft Angle
#1
Correction
#3
#4
#2
Crankshaft Angle
Q000902E
1– 76
Operation Section
7.2 E-EGR System (Electric-Exhaust Gas Recirculation)
(1) General Description
• The E-EGR system is an electronically controlled EGR system. The EGR system recirculates a portion of the exhaust
gases into the intake manifold in order to lower the combustion chamber temperature and reduce NOx emissions.
However, operation of the EGR system may reduce engine power output and affect drivability. For this reason, in the
E-EGR system, the engine ECU controls the EGR to achieve an optimal EGR amount.
Operation Conditions Example
- This operates in the operation region fulfilling the starting conditions below (one example).
Injection Quantity
· Engine Operating Conditions
· · · · · Except during engine warm-up and startup,
does not overheat, etc.
· EGR Operating Range
· · · · · · · · For Engine Medium Load
Engine Speed
Q000501E
(2) Operation
• After the vacuum pump generates a vacuum, the E-VRV (electric-vacuum regulation valve) regulates the vacuum and
directs it to the diaphragm chamber of the EGR valve. In response to this vacuum, the diaphragm pushes the spring
downward, which determines the opening of the EGR valve and controls the EGR volume.
• The EGR cooler, which is provided in the EGR passage between the cylinder head and the intake passage, cools the
EGR in order to increase the EGR volume.
• The EGR cutoff VSV, which opens the diaphragm chamber to the atmosphere when the EGR valve is closed, helps
to improve response.
Diaphragm
Vacuum Pump
Vacuum Damper
EGR Valve
E-VRV
Spring
EGR Shut-Off VSV
Coolant
EGR Cooler
Engine
Control Unit
Exhaust
Manifold
Engine Speed
Accelerator Opening
Intake Air Pressure And
Atmospheric Pressure
Coolant Temperature
Intake Air
Relationship Between Vacuum and EGR Valve Opening
Low
Small
Vacuum
High
EGR Valve Opening
Large
Q000903E
Operation Section
1– 77
To Increase the EGR Quantity
- The E-VRV duty ratio is controlled*1. In the stable condition shown in the bottom center diagram, an increase in the
current that is applied to the coil causes the attraction force FM in the coil to increase. When this force becomes
greater than the vacuum force FV that acts on the diaphragm, the moving core moves downward. Along with this
movement, the port from the vacuum pump to the upper chamber of the diaphragm opens. Consequently, the output vacuum increases, which causes the EGR valve to open and the EGR volume to increase. Meanwhile, because
"increased output vacuum equals increased FV", the moving core moves upward with the increase in FV. When
FM and FV are equal, the port closes and the forces stabilize. Because the vacuum circuit of the EGR is a closed
loop, it maintains the vacuum in a stabilized state, provided there are no changes in the amperage.
< NOTE >
*1 : The engine ECU outputs sawtooth wave signals with a constant frequency. The value of the current is the effective (average) value of these
signals. For details, see the explanation of the HP3 supply pump and SCV.
To Decrease the EGR Volume
- A decrease in the current that is applied to the coil causes FV to become greater than FM. As a result, the diaphragm moves upward. The moving core also moves upward in conjunction with the movement of the diaphragm,
causing the valve that seals the upper and lower diaphragm chambers to open. Consequently, the atmospheric
pressure in the lower chamber enters the upper chamber, thus reducing the output vacuum. This causes the EGR
valve to close and the EGR volume to decrease. Because "decreased output vacuum equals decreased FV", the
moving core moves downward with the decrease in FV. When FM and FV are equal, the port closes and the forces
stabilize.
From Vacuum Pump
To EGR Valve
FV
Valve
Spring
Moving Core
Diaphragm
FM
Coil
Stator Core
FM > FV
EGR Quantity Increased
Atmosphere
FM < FV
EGR Quantity Decreased
Q000904E
1– 78
Operation Section
7.3 Electronically Controlled Throttle (Not Made By DENSO)
(1) General Description
• The electronically controlled throttle is located upstream of the EGR valve in the intake manifold. It controls the throttle
valve at an optimal angle to regulate the EGR gas and reduce noise and harmful exhaust gases.
(2) Operation
• Signals from the engine ECU actuate the stepping motor, which regulates the throttle valve opening.
EGR Control
• To further increase the EGR volume when the EGR valve is fully open, the vacuum in the intake manifold can be increased by reducing the throttle valve opening, which restricts the flow of the intake air.
Noise and Exhaust Gas Reduction
• When the engine is being started, the throttle valve opens fully to reduce the emissions of white and black smoke.
• When the engine is being stopped, the throttle valve closes fully to reduce vibration and noise.
• During normal driving, the throttle valve opening is controlled in accordance with the engine conditions, coolant temperature, and atmospheric pressure.
Stepping Motor
Throttle Valve
Q000905E
Operation Section
1– 79
7.4 Exhaust Gas Control System
(1) General Description
• The exhaust gas control system is provided to improve warm-up and heater performance. This system actuates the
exhaust gas control valve VSV, which is attached to the exhaust manifold. It increases the exhaust pressure to increase the exhaust temperature and engine load, in order to improve warm-up and heater performance.
Vacuum Pump
Exhaust Gas
Control Valve
Air Cleaner
VSV
Turbo Pressure
Sensor
Coolant Temperature
Sensor
Exhaust Gas
Control Valve
EGR Valve Position
Sensor
Mass Airflow Meter
Cylinder
Recognition Sensor
(TDC (G) Sensor)
Accelerator
Position Sensor
Atmospheric
Pressure Sensor
ECU
Warm-Up Switch
Q000906E
(2) Operation
• The exhaust gas control system operates when the warm-up switch is ON, and all the conditions listed below have
been met.
Operation Conditions
- The EGR is operating.
- The coolant temperature is below 70°C.
- The ambient temperature is below 5°C.
- A minimum of 10 seconds have elapsed after starting the engine.
- The engine speed and fuel injection quantity are in the state shown in the graph below.
[Exhaust Gas Control System Operating Range]
Operating Range
Extremely Low Torque
or Engine Speed Range
Injection Quantity
WARM UP
Engine Speed
Q000907E
1– 80
Operation Section
7.5 DPF System (Diesel Particulate Filter)
(1) General Description
• This system reduces emissions of PM (particulate matter). In order to collect PM, a DPF cleaner with built-in catalytic
filter is mounted on the center pipe. The collected PM is handled with combustion processing during operation.
(2) System Configuration
Rail
Intercooler
Intake Air
Pressure Sensor
G2 Injector
EGR Cooler
VNT Actuator
EGR Valve
Equilibrium
Actuator
Supply Pump
DPF (with
Oxidation Catalyst)
Exhaust Gas
Temperature Sensor
ECU & EDU
Differential Pressure Sensor
Exhaust Gas Temperature Sensor
Q000908E
(3) Various Sensors
Exhaust Gas Temperature Sensor
• The exhaust gas temperature sensor is installed to the front and rear of the DPF to detect the temperature in these
positions. The engine ECU controls the exhaust temperature for PM combustion based on the signals from this sen-
Cover
Resistance Value (
Thermistor Element
)
sor. The sensor element is a thermistor.
Exhaust Gas Temperature (
)
Q000909E
Operation Section
1– 81
Differential Pressure Sensor
• The differential pressure sensor detects the difference in pressure at the front and rear of the DPF, and outputs a signal to the engine ECU. The sensor portion is a semiconductor type pressure sensor that utilizes the piezoelectric effect through a silicon element, and amplifies and outputs the voltage with its IC circuit. When PM is collected and
accumulated in the DPF, the filter clogs and the difference in pressure at the front and rear of the DPF increases.
Therefore, based on the signals from this sensor, the engine ECU judges whether or not to subject PM to combustion
VP Output Voltage
processing.
GND
VP
(V)
VC
Pressure (kPa)
Q000910E
(4) Operation
• By optimizing the injection pattern and controlling the exhaust gas temperature based on the exhaust gas temperature
and the difference in pressure at the front and rear of the DPF, PM is collected, oxidized, and self-combusted. When
the exhaust temperature is low, adding after-injection after the main injection raises the exhaust gas temperature to
approximately 250?C and promotes oxidation of the PM. When the PM is collected and accumulated, the post-injection is added and HC is added to the catalyst to raise the catalyst temperature to 600?C, which is the self-combustion
temperature for PM. This combusts the accumulated PM in a short time. The engine ECU controls the A, B, and C
times and the injection times.
TDC
B
A
C
After-Injection
Post-Injection
Q000506E
1– 82
Operation Section
7.6 DPNR SYSTEM (DIESEL PARTICULATE NOx REDUCTION)
(1) General Description
• This system reduces the emissions of PM (particulate matter) and NOx. The DPNR catalyst mounted in the center
pipe collects and regenerates PM and reduces NOx all at the same time. The collected PM is handled with combustion processing during operation.
(2) System Configuration
Exhaust Gas Cleaning
Device Switch
Supply Pump
Exhaust Gas Cleaning
Device Display Lamp
Intake Restriction Valve
Injector
Engine ECU
Exhaust
Retarder VSV
DPNR Catalyst
Oxidation Catalyst
A/F Sensor
Oxidation Catalyst
Before EGR Cooler
Fuel Addition Valve
A/F Sensor
Exhaust Retarder
NSR Differential Pressure Sensor
Exhaust Gas Temperature Sensor
Q000911E
Operation Section
1– 83
8. DIAGNOSIS
8.1 Outline Of The Diagnostic Function
z The diagnostic function enables a system to self-diagnose its own malfunctions. If abnormal conditions occur in the sensors or actuators used in the control systems, the respective systems convert the malfunction signals into codes and
transmit them to the engine ECU. The engine ECU records the transmitted malfunction code into memory. Recorded
codes are output at the diagnostics connector on the vehicle. To inform the driver of the malfunction, the engine ECU
causes the MIL (Malfunction Indicator Light) in the meter to illuminate. Accurate troubleshooting can be performed by
way of the DTCs (Diagnostic Trouble Codes) that are output at the diagnostic connector. For details on actual diagnosis
codes, see the vehicle manual. It is necessary to put the vehicle into the state below before starting inspection.
(1) Pre-Inspection Preparation
• Position the shift lever in "N" or "P".
• Turn OFF the air conditioner.
• Verify that the throttle valve is fully closed.
8.2 Diagnosis Inspection Using DST-1
z The DST-1 can be used in both normal and check modes. Compared to the normal mode, the check mode has a higher
sensitivity to detect malfunctions.
z The check mode inspection is performed when normal codes are output in the normal mode, despite the fact that there
may be malfunctions in the sensor signal systems.
(1) Reading DTCs
1) DST-1 Connection: Connect the DST-1 to the DLC3 terminal.
DLC3
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
Q000914
2) Reading DTCs: Operate in accordance with the instructions
shown on the screen to display the "DTC check" screen. Se-
Diagnostic Trouble Codes (DTC)
1.
lect either the normal or check mode and read the DTC.
···
< NOTE >
If no DTC appears on the screen, there may be a failure
in the engine ECU.
Execute: Execute
Q000915E
Operation Section
1– 84
3) Checking the Freeze Frame Data: If the symptom that outputs a DTC cannot be duplicated, check the freeze frame
data.
4) Erasing DTCs from memory: Operate in accordance with
the instructions shown on the screen to display the "DTC
DTC (ECD Erasure)
check" screen. Select "Erase DTCs" to erase the DTCs.
This will erase the DTC and freeze frame data.
Do you wish to proceed?
< NOTE >
If it is not possible to erase the DTC, turn the ignition
switch OFF, and repeat the process.
5) Wiring Harness and Connector Open Circuit Check
NG : - OK : +
Q000916E
< NOTE >
If the DTC output during a diagnostic inspection (in the
check mode) has identified the system with a malfunction,
use the method indicated below to narrow down the area
of the malfunction.
• Erasing DTCs from memory: After reading the DTCs in check mode, erase the DTCs from memory.
• Starting the Engine: Select the check mode and start the engine.
• Malfunctioning system check 1: While the engine is running at idle, shake the wiring harness and connectors of the
system that output the malfunction during the diagnosis (check mode) inspection.
• Malfunctioning system check 2: If the MIL (Malfunction Indicator Light) illuminates when the wiring harness and connectors are shaken, there is a poor contact in the wiring harness or connectors in that area.
8.3 Diagnosis Inspection Using The MIL (Malfunction Indicator Light)
z Before reading a DTC, turn the ignition switch ON to make sure the MIL (Malfunction Indicator Light) illuminates.
z Inspections in the check mode cannot be performed.
(1) Reading DTCs
Short circuiting the connector
• Using the STT, short circuit between DLC1 terminals 8 (TE1) and 3 (E1) or between DLC3 terminals 13 (TC) and 4
(CG).
DLC1
DLC3
E1
TC
1 2
3
4
5 6
16 15 14 13 12 11 10 9
18
19
TE1
7 8
9
12 13 14
15
10 11
20
16 17
21
8 7 6 5 4 3 2 1
22 23
CG
Q000917E
< CAUTION >
Never connect the wrong terminals of the connectors as this will lead to a malfunction.
Operation Section
1– 85
Reading DTCs 1
• Turn the ignition switch ON and count the number of times the MIL (Malfunction Indicator Light) blinks
· Normal Operation
0.26sec
0.26sec
Repeat
ON
OFF
Malfunction
Indicator Light
0.26sec
Jump Terminals TE1 and TC
· Malfunction (Codes "12" and "23" are output.)
0.52sec 1.5sec
2.5sec
1.5sec
4.5sec
4.5sec
Repeat Thereafter
ON
OFF
0.52sec
0.52sec
Jump Terminals TE1 and TC
Q000918E
< NOTE >
• If the MIL (Malfunction Indicator Light) does not output a code (the light does not blink), there may be an open circuit in
the TC terminal system or a failure in the engine ECU.
• If the malfunction indicator light is constantly ON, there may be a short (pinching) in the wiring harness or a failure in
the engine ECU.
• If meaningless DTCs are output, there may be a malfunction in the engine ECU.
• If the MIL (Malfunction Indicator Light) illuminates without outputting a DTC while the engine operates at a minimum
speed of 1000rpm, turn the ignition switch OFF once; then resume the inspection.
Reading DTCs 2
• If an abnormal DTC has been output, check it against the DTC list.
Erasing DTCs from memory
• Remove the ECD fuse (15A); after 15 seconds have elapsed, re-install the fuse.
Engine Compartment Relay Block
ECD Fuse (15A)
Q000919E
< CAUTION >
After completing the inspection of the ECD system, erase the DTC memory, and make sure the normal code is output.
1– 86
Operation Section
8.4 Throttle Body Function Inspection
< CAUTION >
• Be sure to inspect the function of the throttle body after it has been disassembled and reassembled, or after any of its
components have been removed and reinstalled.
• Verifying Throttle Motor: Verify that the motor generates an operating sound when the ignition switch is turned ON.
Also, verify that there is no interference sound.
(1) Erasing DTCs
1) Connect the DST-1 to the DLC3 connector.
DLC3
16 15 14 13 12 11 10 9
8 7 6 5 4 3 2 1
Q000914
2) Operate in accordance with the instructions shown on the
screen to display the "DTC check" screen. Select "Erase
DTC (ECD Erasure)
DTCs" to erase the DTCs.
This will erase the DTC and freeze frame data.
Do you wish to proceed?
NG : - OK : +
Q000916E
(2) Inspection
• Start the engine and make sure the MIL (Malfunction Indicator Light) does not illuminate and the engine speed is within standards when the air conditioner is turned ON and OFF after the engine has warmed up.
< CAUTION >
Make sure no electrical load is applied.
(3) Final Inspection
• After inspecting the throttle body function, drive test the vehicle to confirm that operation is normal.
Operation Section
1– 87
9. END OF VOLUME MATERIALS
9.1 Particulate Matter (PM)
z At high concentration levels, this substance is known to affect the respiratory system. It consists of soluble organic matter such as unburned oil, unburned diesel fuel, and other "soluble organic matter" in the exhaust gases, and insoluble
organic matter such as soot (black smoke) and sulfuric acid gas.
9.2 Common Rail Type Fuel Injection System Development History And
The World’s Manufacturers
z The conventional injection pump faced certain issues such as injection pressure that depended on engine speed, and
limits on the maximum fuel pressure. Other types of injection control such as pilot injection also faced some difficulties.
Addressing these issues in a revolutionary manner, DENSO led the world by introducing a commercial application of
the common rail fuel injection system.
z Two types of common rail fuel injection systems are in use today. One is the common rail system that pressurizes the
fuel and injects it directly into the cylinders. DENSO was the first in the world to introduce a commercial application of
this system. This system, which is undergoing further development, has been adopted in passenger car applications.
Other companies, such as R. Bosch, Siemens, and Delphi also offer their commercial versions of this system today. The
other system is the Hydraulic Electric Unit Injection (HEUI) system, which was developed by Caterpillar in the United
States. This system uses pressurized engine oil to pressurize the fuel by actuating the piston of the nozzle (injector)
through which the pressurized fuel is injected.
1– 88
Operation Section
9.3 Higher Injection Pressure, Optimized Injection Rates, Higher Injection
Timing Control Precision, Higher Injection Quantity Control Precision
(1) Higher Injection Pressure
• The fuel that is injected from the nozzle turns into finer particles as the fuel injection pressure increases. This improves
combustion and reduces the amount of smoke contained in the exhaust gases. Initially, the maximum injection pressure of the in-line pump (A type) and the distributor pump (VE type) was 60 MPa. Due to advancement in high-pressure applications, there are some recently developed fuel injection systems that inject fuel at a pressure of 100 MPa
or higher. The second-generation common rail system injects fuel at an extremely high pressure of 180 MPa.
A Type Pump
Mechanical Pump
Distributor Type Pump
NB Type Pump
1 MPa is
approximately 10.2kgf/cm2
ECD V3 Pump
ECD V Series
(1st Generation)
ECD V4 Pump
120
HP0Pump
120
145
HP2Pump
Common Rail Series
(2nd Generation) HP3,4Pump
185
50
100
150
200
Injection Pressure (MPa)
Q000920E
(2) Optimized Injection Rates
• The injection rate is the ratio of the changes in the fuel quantity that is injected successively from the nozzle within a
given unit of time.
High Injection Rate
Injection Quantity
Injection Rate
t
Q000921E
Operation Section
1– 89
• As the injection pressure increases, the injection rate increases accordingly. The increase in injection rate leads to an
increase in the volume of the air-fuel mixture that is created between the start of injection until ignition (the ignition lag
period). Because this mixture is subsequently combusted at once, it creates noise (diesel knock) and NOx. For this
reason, it is necessary to appropriately control the injection rate by maintaining a low injection rate at the beginning
of injection and supplying a sufficient quantity after the ignition. To meet this need, two-spring nozzles have been
adopted and a pilot injection system has recently been developed.
Injection Quantity
Common Rail System
Injection Rate Control
Injection Quantity
2-Spring Nozzle
Injection Rate
Pilot Injection
Q000922E
(3) Higher Injection Timing Control Precision
• Reducing exhaust gas emissions and fuel consumption and optimizing the injection timing are important. It is extremely difficult to achieve the desired exhaust emission reduction levels through methods that adjust the injection
timing according to speed (or centrifugal force), such as the conventional mechanical timer. For this reason, electronically controlled systems have been adopted to freely and precisely control the injection timing in accordance with the
engine characteristics.
ti on
Q ua
ntity
Engine Speed
Injec
t i on
Advance
Angle
Injec
Mechanical Timer
Advance
Angle
Electronic Control Type
Q ua
ntity
Engine Speed
Q000923E
(4) Higher Injection Quantity Control Precision
• Power output adjustment in a diesel engine is accomplished by regulating the fuel injection quantity. Poor injection
quantity control precision leads to increased exhaust gas emissions, noise, and poor fuel economy. For this reason,
electronically controlled systems have been developed to ensure high precision injection quantity control.
1– 90
Operation Section
9.4 Image Of Combustion Chamber Interior
z With conventional injection methods, because an excessive quantity of fuel was injected in the initial period, the explosion pressure rose excessively, leading to the generation of noise such as engine knocking sounds. To improve this
condition through pilot injection, initially only the necessary and adequate quantity of fuel is injected. At the same time,
the combustion chamber temperature is raised, and main injection combustion is assisted while working to prevent
noise and vibration.
Conventional Injection
Pilot Injection
Q000924E
Repair Section
2– 91
1. DIESEL ENGINE MALFUNCTIONS AND DIAGNOSTIC METHODS (BASIC KNOWLEDGE)
1.1 Combustion State and Malfunction Cause
z Depending on the state of combustion in a diesel engine, diesel knock as well as the color of the exhaust gas may
change. Subsequently, the cause of engine malfunctions can be ascertained from changes in diesel knock and exhaust
gas color.
Knocking
Sound
Black
Smoke
White
Smoke
Q002310E
(1) Diesel Knock
• When fuel mixed with air during the ignition lag period (from the time injection begins until the fuel is ignited) reaches
ignition temperature, the mixture is combusted in one burst. The pressure in the combustion chamber at this time rises
as the quantity of the air-fuel mixture increases. If a large amount of air-fuel mixture is created during the ignition lag
period, the pressure in the combustion chamber will rise rapidly. The pressure waves resulting from fuel ignition vibrate the cylinder walls and engine components, which generates noise. The generated noise is called "knocking".
To some extent, knocking is unavoidable in engines that use a self-ignition system.
Cylinder Internal Pressure
Pressure Increase
Ignition
Start of
Injection
T.D.C. Crankshaft Angle
Q002311E
Cause of Diesel Knocking
1
Early Injection Timing
2
Cold Engine
3
Intake air temperature is low.
4
Poor Engine Compression
5
Poor Fuel Combustibility
A large quantity of air-fuel mixture is created prior to ignition, or the
cetane value is high.
Ignition occurs late without an increase in temperature.
Ignition occurs late (low cetane value.)
Repair Section
2– 92
(2) White Smoke
White smoke: Uncombusted fuel that has been vaporized and then discharged.
• White smoke is generated when combustion occurs at a relatively low temperature, resulting in the exhaust of uncombusted fuel and oil particles. White smoke is most likely to be generated when combustion chamber temperature
is low.
Source of White Smoke
1
Late Injection Timing
2
Cold Engine
3
Poor Fuel Combustibility
4
Rise and Fall of Oil Pressure
Fuel is injected when the piston is in the down stroke.
Ignition occurs late and combustion is prolonged.
Oil undergoes partial thermal breakdown.
(3) Black Smoke
Black smoke: Fuel that has been baked into soot and discharged.
• Black smoke is often referred to as just "smoke". Black smoke is generated when the injected fuel is poor in oxygen.
As the fuel is exposed to high temperatures, thermal breakdown occurs, leaving carbon behind. Black smoke occurs
when the injected fuel quantity is too large, or when the air-fuel mixture is rich due to an insufficient quantity of air.
Source of Black Smoke
1
Large Fuel Injection Quantity
Air-fuel mixture becomes rich.
2
Low Intake Air Quantity
Air quantity is insufficient due to air filter clogging.
3
Poor Fuel Atomization
The ratio of fuel to air worsens.
4
Retarded Fuel Injection Timing
Air-fuel mixing time is insufficient.
1.2 Troubleshooting
Troubleshooting cautions
z Observe the following cautions to avoid decreased engine performance and fuel injector malfunctions.
• Use the designated fuel.
• Avoid water and foreign material intrusion into the fuel tank.
• Periodically check and clean the filter.
• Do not unnecessarily disassemble sealed components.
Troubleshooting notes
z The cause of malfunctions is not necessarily limited to the pump itself, but may also be related to the engine and/or fuel
systems. Further, the majority of malfunctions are the result of user error, and often can often be resolved through simple
checks and maintenance. Avoid any hasty removal of system components.
Basic Check Items
1
Engine Oil
7
Fuel Supply to the Pump
2
Coolant
8
Injector Injection Status
3
Fan Belt
9
Supply Pump Timing Mark
4
Air Cleaner
10
5
Battery and Terminals
11
6
Fuel System Leaks
Check for Loose or Disconnected Connectors, and
Modifications
Idle Speed Status
Repair Section
2– 93
2. DIAGNOSIS OVERVIEW
2.1 Diagnostic Work Flow
Diagnostic Procedures
1
Receive malfunctioning vehicle
2
Question the user to verify the nature of the
malfunction.
3
Does the malfunction reoccur?
Refer to "Actions for Non-Reoccurring Malfunctions."
4
Verify the malfunction symptom at the actual
vehicle.
5
Use the DST-2 to check for any DTCs.
Proceed with diagnostics while referencing the
DTC chart in the repair manual for the appropriate vehicle.
6
Use the DST-2 "Data Monitor" function to per-
Proceed with diagnostics while referencing the
form checks while monitoring each input and
repair manual for the appropriate vehicle.
output signal.
7
Use the DST-2 active test function to operate
Proceed with diagnostics while referencing the
each output device with the ignition switch in the
repair manual for the appropriate vehicle.
ON position. Check for any abnormalities in
either the electrical circuits or the output
devices.
8
Was the malfunction cleared?
Return to step 3.
2– 94
Repair Section
2.2 Inquiries
z Use the Common Rail System (CRS) troubleshooting questionnaire to consult with the customer and adequately grasp
the malfunction symptoms.
< NOTE >
Do not ask random questions. Rather, ask questions that will aid in narrowing down the possible malfunctioning system
while making educated guesses based on the actual symptoms.
Questioning points
z Use the following questions as a basis to fully grasp the malfunction.
• What?: Malfunction symptoms
• When?: Date, time, frequency of occurrence
• Where?: Road conditions
• Under what conditions?: Driving conditions, engine operating conditions, weather
• How?: Impression of how the symptoms occurred.
CRS troubleshooting questionnaire
z When the vehicle is received at the service center, it is necessary to verify the "malfunction symptoms" and the "generated malfunction data" with the customer. Consult with the customer using the CRS troubleshooting questionnaire. The
troubleshooting questionnaire is necessary for the following reasons.
Reasons
• There are cases when the malfunction symptoms cannot be reproduced at the service center.
• The customer's complaint is not always limited to the malfunction.
• If the person performing repairs is not working from the correct malfunction symptoms, man-hours will be wasted.
• The questionnaire can aid the service center in diagnosing, repairing and verifying repair work.
Questioning Results
Inspection Results
Q002315E
Repair Section
2– 95
(1) Questionnaire
CRS Troubleshooting Questionnaire
Vehicle Model
Receiving Date
Service History
Frame No.
Date Registered
Registration No.
Occurrence Date
Odometer Reading
No / Yes (
times)
Main Area and Purpose of Use
Previous Vehicles Driven:
Other Customer Information
Indications from the Customer
MIL Illumination No / Yes (
System Conditions
Questioning
Results
Occurrence Speed
( ) km/hr
Shift Position
( ) Range
At Start-Up
Directly after Start-Up
Up to ( ) Minutes after Start
Up to ( ) Minutes into Driving
When Cold
When Warm
During Operation
Other (
)
)
Road Surface
Driving Conditions
During Take-Off
While Cruising
When Accelerating
When Decelerating
When Braking
When Turning
When Stopped
No Relationship
Other (
)
Other
Flat
Uphill
Downhill
Dry, Sealed road
Wet, Sealed Road
Unsealed Road or
Rough Road Surface
Snow-Covered or Icy Road
Potholes, Manholes, etc.
Other (
)
Accelerator
Opening
(
)%
Outside Air
Temperature
o
(
) C
Weather
(
)
Frequency of Occurrence
Normal
Only Once
Occasionally
( ) Times per Day
( ) Times per Week
( ) Times per Month
Additional Items
DTC Check
Illuminated
No
Yes
DTC Normal
Abnormal DTC (All Codes)
Fuel Pressure when Engine is Stopped
1 Minute after Turning Engine OFF
Malfunction Details: Time of occurrence, place and driving conditions during reoccurrence.
Inspection
Results
Reoccurrence
Conditions
Occurs Regularly
Occurs Occasionally
Continues to Appear
After One Occurrence
Does Not Reoccur
Q002316E
2– 96
Repair Section
2.3 Non-Reoccurring Malfunctions
z In cases where the malfunction does not reoccur, perform the actions below to determine the cause of the malfunction.
Malfunction Symptom
Idle Speed,
Fully Dis-
Action
charged Battery
Engine will not
Start
Engine Stall,
Sputtering,
Poor Acceleration
Verify that there is no DTC stored in the memory.
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
No
Yes
Yes
No
No
Yes
No
No
Yes
Yes
Yes
Yes
Use the questionnaire as a basis to perform a reoccurrence test in
"Reoccurrence" mode. Use this data (engine ECU voltage value, etc.)
to determine the cause of the malfunction.
Assume that an electrical system wiring harness or connector
is the cause of the malfunction.
Shake the wiring by hand to
Q002317
check whether a malfunction
occurs and a DTC is generated.
Assume that an electrical system female connector terminal is the
cause of the malfunction and verify that the connection points are not
defective.
Recommended Tool: KOWA Precision Handling
Feeler Gauge Set (KLM-10-20)
Depending on the terminal, a matching
size may not be available
Insert the male terminal that
matches the shape of the
female terminal and check
for looseness.
Q002318
Use a dryer to heat the accelerator pedal position sensor and
other electronic components.
Check for changes in the voltQ002319
age value (resistance value).
< CAUTION >
• Do not exceed 60°C (still touchable by hand) when heating.
• Do not remove the component cases and add heat directly to
electronic parts.
Verify whether malfunction symptoms occur under heavy engine
loads (headlights, A/C, wiper, etc. switches ON.)
If any commercial electrical products have been installed, remove
such products and verify whether the malfunction symptoms occur.
Repair Section
2– 97
Malfunction Symptom
Idle Speed,
Action
Fully Discharged Battery
Engine will not
Start
Engine Stall,
Sputtering,
Poor Acceleration
If it is likely that the malfunction
occurs in rainy or high-tempera-
Mist State
ture weather, spray the vehicle
with water and verify whether
Q002320E
the malfunction occurs.
< CAUTION >
• Do not spray water directly into the engine compartment.
Spray water in mist form on all surfaces of the radiator to indirectly change temperature and humidity.
• Do not spray water directly on electrical parts.
No
Yes
Yes
2– 98
Repair Section
3. DTC READING (FOR TOYOTA VEHICLES)
3.1 DST-2
z The DST-2 can check for DTCs in either normal or check mode. In comparison to the normal mode, the check mode
has higher sensitivity in detecting malfunctions. Check mode is used when detection is not possible in normal mode,
regardless of the assumed abnormality.
3.2 DTC Check (Code Reading via the DST-2)
z Connect the DST-2 to the DLC3 connector.
z Operate the DST-2 in accordance with the instructions shown on the display to view the "DTC check" screen. Select
either the normal or check mode to verify the DTC.
3.3 DTC Memory Erasure (via the DST-2)
z To erase DTC codes, follow the instructions on the display to view the "DTC and Freeze Data Erasure" screen.
DTC (ECD Erasure)
This will erase the DTC and freeze frame data.
Do you wish to proceed?
NG : - OK : +
Q000916E
< CAUTION >
• If the DTC cannot be erased, cycle the ignition switch OFF and back ON, and then perform code erasure again.
• Do not use the DST-2 to erase the DTC until the cause of the malfunction is clear.
Repair Section
2– 99
4. TROUBLESHOOTING BY SYSTEM
4.1 Intake System Diagnosis
Clogged air cleaner element
1
Clogged air cleaner element
Clean or replace the air cleaner.
NG
OK
2
Repair or replace the malfunctioning compo-
Check the suction path for leaks.
• Suction path joints
NG
nent.
• Suction pipes, hoses
OK
Normal
4.2 Fuel System Diagnosis
Clogged air cleaner element
1
Add fuel or replace components (clean tank.)
Fuel system check (remaining fuel quantity, fuel
NG
properties)
• Check the amount of fuel remaining in the
tank.
• Check the condition of the fuel. Request
engine analysis from a third party as necessary.
- Color (no color, brownish, milky)
- Odor (kerosene, heavy oil, irritating odor)
- Separation of materials (water, foreign
objects)
- Viscosity (high/low viscosity, wax consistency)
OK
2– 100
2
Repair Section
Restore the fuel tank.
Fuel tank interior check (modification/additions,
position of fuel pipe inlet/outlet, clogging and
NG
holes)
• Check the tank for modifications or additions.
Consult with the user.
- Fuel inlet/outlet position, tank piping
- Foreign material inside the tank, water separation
- Tank-internal Zn cladding
- Check the tank-internal fuel piping for the
following.
- Inlet/outlet position (below position "E")
- Inlet clogging, bent or deformed piping
(crushed pipe)
- Crushed piping connections
OK
3
Tank-external fuel path conditions (crushed
hose, clogging, air introduction at hose connec-
Repair or replace the hose.
NG
tion)
• Check the condition of the hose.
- Crushing around bands, over-bending
- Pinched or crushed by other parts
• Air introduction through fuel system connection points
- Looseness
- Hose deterioration (Verify by hand or visually that there is no rubber hardening/splitting.)
< CAUTION >
Be cautious when vacuum pressure is
present, as air will be drawn into the
hose.
OK
4
Replace the filter, and drain water from the sedi-
Primary filter, sedimentor check
• Check for primary filter clogging and dirt.
NG
mentor.
• Check sedimentor water volume.
OK
5
Tighten or replace the priming pump.
Looseness at priming attachment point check
• Check the following.
- Looseness at the priming attachment point
- Does the piston stick out?
- Fuel leakage (oozing)
OK
NG
Repair Section
6
2– 101
Clean the gauze filter, fuel filter and fuel piping
Filter (supply pump inlet) clogging
NG
• Fuel filter
system, or replace the filters.
- Check for fuel delivery from the priming
pump.
• Gauze filter
- Visually check for clogging due to foreign
material.
OK
7
Check the engine.
Oil level increase (engine internal leak)
• Verify whether the oil level increases on the
NG
oil level gauge.
OK
8
High-pressure piping and CRS component
(injector supply pump, rail) fuel leaks (engine
Repair leaking high-pressure piping or replace
NG
leaking parts.
external leak) (Refer to "(2) Fuel leak check".)
• Connect the DST-2 to the diagnostic connector. Activate the "Fuel Leak Check Function"
within the active test.
• Visually check and specify areas that leak
fuel.
< CAUTION >
In the event of a large fuel leak downstream of the flow damper, be aware
that fuel flow will stop and the leak will
cease due to flow damper operation.
OK
Normal
(1) Fuel pressure test procedure
• Connect the DST-2 to the vehicle-side test connector.
- With the vehicle idling, verify the rail pressure displayed on the DST-2.
System selection screen: Rail a ECU Data Monitor
Item Name (Abbrevi-
Explanation
Check Conditions
Reference Value
ated)
Items of Importance
During an Abnormality
Rail Pressure (RP)
• Displays
the
fuel Following
pressure in the rail.
• Display
range:
MPa to 255 MPa
engine Fuel pressure in the PCR1, PCR2 signals
warm-up, when the rail is displayed within (rail assembly)
0 engine is rotating
a range of 30 MPa to
160 MPa.
2– 102
Repair Section
(2) Fuel leak check
• Connect the DST-2 to the vehicle-side test connector.
• With the vehicle idling, perform the active test by following the instructions on the DST-2 display.
System selection screen: TCCS a Active Test
Item Name
High-Pressure Fuel System Check
Description
Control Conditions
Raise engine speed to 2000 rpm, and
• Following engine warm-up, when
then use the active test to place the
fuel inside the rail under high pressure.
the engine is at idle speed
• The vehicle speed sensor is operating normally, and speed is 0 km/h.
< CAUTION >
Engine
speed
cannot
be
raised by stepping on the
accelerator pedal.
• Verify that there are no fuel system leaks during the active test (when fuel pressure is being applied to the rail.)
4.3 Basics of Electrical/Electronic Circuit Checks
(1) ECU terminal voltage and waveform measurements
• When measuring the voltage and resistance of each terminal, insert the multimeter probe into the rear side of the
wiring harness connector. If connectors are too small for the probe to be inserted easily, insert a fine metal wire into
the rear of the connector and touch the wire to the probe.
< NOTE >
The number of each terminal can be seen from the rear side of the wiring harness.
Engine ECU Side
Ground
Ground
Wiring Harness
Side
Ground
Q002326E
Repair Section
2– 103
(2) Open circuit check
• When dealing with a wiring harness open circuit like that depicted in diagram 1, check continuity and/or voltage to
determine the location of the open circuit.
Diagram 1
Engine ECU
Sensor
1
Open
Circuit
2
C
1
1
1
2
2
2
B
A
Q002327E
Continuity Check
1) Remove connectors "A" and "C", and then measure resis-
Diagram 2
tance between the two.
Engine
ECU
1
Sensor
2
C
Measure resistance while gently shaking the wiring har-
2
B
1Ω or less
< NOTE >
1
2
Standard Value
ness up and down, and side-to-side.
A
Q002328E
2) As shown in diagram 2, there is no continuity (open circuit)
between terminal 1 of connector "A" and terminal 1 of connector "C". However, there is continuity between terminal 2
of connector "A" and terminal 2 of connector "C". Therefore,
there is an open circuit between terminal 1 of connector "A"
and terminal 1 of connector "C".
3) Remove connector "B" and measure the connector resis-
Diagram 3
Engine
ECU
tance.
4) As shown in diagram 3, there is continuity between terminal
1 of connector "A" and terminal 1 of connector "B1". Howev-
Sensor
er, there is no continuity (open circuit) between terminal 1 of
1
2
C
1
1
2
2
B2 B1
connector "B2" and terminal 1 of connector "C". Therefore,
1
there is an open circuit between terminal 1 of connector "B2"
2
A
and terminal 1 of connector "C".
Q002329E
Repair Section
2– 104
Voltage Check
1) For the circuit that applies voltage to the ECU connector ter-
Diagram 4
minals, check for an open circuit by performing a voltage
check.
0V
Sensor
C
1
2
2) As shown in diagram 4, with all connectors connected, mea-
5V
sure the voltage for the ECU 5 V output terminal between
5V
B
1
2
A
the body ground and terminal 1 of connector "A". Next mea-
1
2
sure voltage for terminal 1 of connector "B" and terminal 1 of
connector "C" in the same fashion.
3) The faulty circuit and measurement results are shown be-
Q002330E
low.
• Voltage between terminal 1 of connector "A" and the body ground is 5
V.
Measurement
Results
• Voltage between terminal 1 of connector "B" and the body ground is 5
V.
• Voltage between terminal 1 of connector "C" and the body ground is 0
V.
There is an open circuit in the wiring
Faulty Item
harness between terminal 1 of connector "B" and terminal 1 of connector "C".
(3) Short circuit check
• As shown in diagram 5, if there is a short in the wiring harness ground, perform a "Ground Continuity Check" to determine the cause of the short.
Diagram 5
Engine ECU
Sensor
Short
Circuit
%
$
#
Q002331E
Repair Section
2– 105
Ground Continuity Check
1) Remove connector "A" and connector "C", and then mea-
Diagram 6
sure the resistance respectively between terminals 1 and 2
of connector "A" and ground.
Engine
ECU
1
2
Sensor
1
2
C
1
2
B
1Ω or less
Standard Value
< NOTE >
Measure resistance while gently shaking the wiring har-
A
ness up and down, and side-to-side.
Q002332E
2) As shown in diagram 6, there is continuity between terminal
1 of connector "A" and the body ground (short circuit). However, there is no continuity between terminal 2 of connector
"A" and the body ground. Therefore, there is a short circuit
between terminal 1 of connector "A" and terminal 1 of connector "C".
3) Remove connector "B" and measure the resistance be-
Diagram 7
Engine
ECU
tween terminal 1 of connector "A" and the body ground, and
between terminal 1 of connector "B2" and the body ground.
4) The faulty circuit and measurement results are shown be-
Sensor
low.
1
2
C
1
1
2
2
B2 B1
1
Measurement
2
Results
A
• There is no continuity between terminal 1 of connector "A" and the body
ground.
Q002333E
• There is continuity between terminal
1 of connector "B2" and the body
ground.
Faulty Item
There is a short circuit between terminal
1 of connector "B2" and terminal 1 of
connector "C".
2– 106
Repair Section
(4) Connector connection fault verification method
• Simultaneously perform the data monitor and connector voltage measurements.
Ex.) Coolant temperature sensor
1. Read the "Coolant Temperature Output Voltage" value using the DST-2 data monitor.
2. Measure the voltage directly from the corresponding ECU terminal.
If "1" is unsatisfactory and "2" is satisfactory, the connector connection is judged as faulty.
Since some malfunctions only occur intermittently, measure voltage while pulling and shaking the
wires in order to try to get the malfunction to reoccur.
Voltage Measurement
No.2 - 34P
35
62
No.5 - 31P
41
137
69
162
143
167
Q002334E
Repair Section
2– 107
5. TROUBLESHOOTING
5.1 Troubleshooting According to Malfunction Symptom (for TOYOTA Vehicles)
(1) Malfunction Indicator Lamp (MIL) is lit.
Description
The check engine warning light is lit when the engine is running, or before the engine is started.
Possible Cause
The DTC is recorded in the engine ECU.
Clogged air cleaner element
1
Connect the DST-2 and read the DTC.
Inspect the check engine warning light circuit.
NG
OK
Troubleshoot the corresponding DTC.
(2) The engine is hard to start.
Description
The starter turns at normal speed, but the engine takes too long to start.
Possible Cause
• Start signal circuit
• Glow control system
• Crankshaft position sensor
• Engine ECU power supply circuit
• Injector
• Supply pump
• Cylinder recognition sensor
Clogged air cleaner element
1
Repair the glow control system. (Refer to the
Use the DST-2 to verify whether the coolant
temperature is at the glow system operating
NG
glow control system check procedure issued by
the vehicle manufacturer.)
temperature. In addition, verify whether battery
voltage is being supplied to the glow plugs at
the designated times.
OK
2
Check the crankshaft position sensor. (Refer to
Use the DST-2 to monitor engine speed while
cranking the engine. Verify whether engine
speed is being correctly output.
NG
the crankshaft position sensor check procedure
issued by the vehicle manufacturer.)
2– 108
Repair Section
OK
3
Repair or replace the cylinder recognition sen-
Verify the output waveform of the cylinder recognition sensor. (Refer to the cylinder recogni-
NG
sor and/or the corresponding circuit.
tion sensor check procedure issued by the
vehicle manufacturer.)
OK
4
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
5
Repair the start signal circuit.
Verify whether there is a start signal when
cranking the engine by checking the engine
NG
ECU start signal terminal.
OK
6
Repair the engine ECU power supply.
Check the engine ECU power supply. (Refer to
the engine ECU power supply circuit diagram
NG
issued by the vehicle manufacturer.)
OK
7
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 109
(3) The engine stalls when idling.
Description
The engine stalls after starting or when idling.
Possible Cause
• Crankshaft position sensor
• Engine ECU power supply circuit
• Injector
• Supply pump
• Engine cooling system
• Start signal circuit
Clogged air cleaner element
1
Verify that the engine is not overheated.
Repair the engine cooling system.
NG
OK
2
Repair or replace the crankshaft position sensor
Check the crankshaft position sensor output
waveform. (Refer to the crankshaft position sen-
NG
and/or the corresponding circuit.
sor check procedure issued by the vehicle manufacturer.)
OK
3
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
4
Repair the start signal circuit.
Verify whether there is a start signal when
cranking the engine by checking the engine
NG
ECU start signal terminal.
OK
5
Repair the engine ECU power supply.
Check the engine ECU power supply. (Refer to
the engine ECU power supply circuit diagram
NG
issued by the vehicle manufacturer.)
OK
6
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
2– 110
Repair Section
(4) The engine cranks normally, but does not start.
Description
The engine is cranked at the normal speed, but does not start.
Possible Cause
• Crankshaft position sensor
• Engine ECU power supply circuit
• Injector
• Supply pump
• Start signal circuit
Clogged air cleaner element
1
Repair the glow control system. (Refer to the
Use the DST-2 to verify whether the coolant
temperature is at the glow system operating
NG
glow control system check procedure issued by
the vehicle manufacturer.)
temperature. In addition, verify whether battery
voltage is being supplied to the glow plugs at
the designated times.
OK
2
Check the crankshaft position sensor. (Refer to
Monitor engine speed while cranking the
engine. Verify whether engine speed is being
NG
the crankshaft position sensor check procedure
issued by the vehicle manufacturer.)
correctly output.
OK
3
Repair the start signal circuit.
Verify whether there is a start signal when
cranking the engine by checking the engine
NG
ECU start signal terminal.
OK
4
Repair the engine ECU power supply.
Check the engine ECU power supply. (Refer to
the engine ECU power supply circuit diagram
NG
issued by the vehicle manufacturer.)
OK
5
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
6
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 111
(5) Idle instability following engine start
Description
Idle speed after starting the engine is abnormal.
Possible Cause
• Injector
• Supply pump
• Fuel filter
• Engine ECU
• Rail pressure sensor
Clogged air cleaner element
1
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
2
Check the fuel filter.
Replace the fuel filter.
NG
OK
3
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive cir-
NG
cuit.
cuit diagram issued by the vehicle manufacturer.)
OK
4
Repair or replace the rail pressure sensor and
Check the rail pressure sensor and the corresponding circuit. (Refer to the rail pressure sensor check procedure issued by the vehicle
manufacturer.)
OK
Troubleshooting complete
NG
the corresponding circuit.
Repair Section
2– 112
(6) The engine returns to idle speed too slowly, or does not return at all.
Description
The time required for the engine to return to idle speed is longer than normal, or the engine does not return to idle
speed.
Possible Cause
• Accelerator position sensor
• Injector
• Supply pump
Clogged air cleaner element
1
Repair or replace the accelerator position sen-
Perform the accelerator pedal position sensor
function check. (Refer to the accelerator posi-
NG
sor and/or the corresponding circuit.
tion pedal sensor check procedure issued by
the vehicle manufacturer.)
OK
2
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
3
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 113
(7) Rough idle
Description
Idle speed fluctuates, causing the engine to vibrate.
Possible Cause
• Engine cooling system
• Crankshaft position sensor
• Engine
• Supply pump
• Injector
Clogged air cleaner element
1
Check parts that may be a source of abnormal
Repair the engine.
NG
engine vibration.
OK
2
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
3
Verify that the engine is not overheated.
Repair the engine cooling system.
NG
OK
4
Repair or replace the crankshaft position sensor
Check the crankshaft position sensor. (Refer to
the crankshaft position sensor check procedure
NG
and/or the corresponding circuit.
issued by the vehicle manufacturer.)
OK
5
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
2– 114
Repair Section
(8) The engine stalls when decelerating.
Description
The engine suddenly stops when decelerating.
Possible Cause
• Engine cooling system
• Crankshaft position sensor
• Engine ECU power supply circuit
• Supply pump
• Injector
• Start signal circuit
Clogged air cleaner element
1
Verify that the engine is not overheated.
Repair the engine cooling system.
NG
OK
2
Repair or replace the crankshaft position sensor
Check the crankshaft position sensor. (Refer to
the crankshaft position sensor check procedure
NG
and/or the corresponding circuit.
issued by the vehicle manufacturer.)
OK
3
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
4
Repair the start signal circuit.
Verify whether there is a start signal when
cranking the engine by checking the engine
NG
ECU start signal terminal.
OK
5
Repair the engine ECU power supply.
Check the engine ECU power supply. (Refer to
the engine ECU power supply circuit diagram
NG
issued by the vehicle manufacturer.)
OK
6
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 115
(9) Poor engine output, poor acceleration
Description
Deficient engine performance.
Possible Cause
• EGR system
• Injector
• Mass Air Flow (MAF) meter
• Crankshaft position sensor
• Accelerator position sensor
• Boost pressure sensor
• Supply pump
• Start signal circuit
• Air cleaner, duct
Clogged air cleaner element
1
Check for air cleaner clogging and/or damage.
Replace the air cleaner or repair the air duct.
NG
OK
2
Verify that the engine is not overheated.
Repair the engine cooling system.
NG
OK
3
Repair or replace the crankshaft position sensor
Check the crankshaft position sensor. (Refer to
the crankshaft position sensor check procedure
NG
and/or the corresponding circuit.
issued by the vehicle manufacturer.)
OK
4
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
5
Repair the start signal circuit.
Verify whether there is a start signal when
cranking the engine by checking the engine
NG
ECU start signal terminal.
OK
6
Repair or replace the MAF meter and/or the cor-
Check the MAF meter and the corresponding
circuit. (Refer to the MAF meter check procedure issued by the vehicle manufacturer.)
OK
NG
responding circuit.
2– 116
7
Repair Section
Repair or replace the EGR system.
Check the Exhaust Gas Recirculation (EGR)
system. (Refer to the EGR system check proce-
NG
dure issued by the vehicle manufacturer.)
OK
8
Repair or replace the accelerator position sen-
Perform the accelerator pedal position sensor
function check. (Refer to the accelerator posi-
NG
sor and/or the corresponding circuit.
tion pedal sensor check procedure issued by
the vehicle manufacturer.)
OK
9
Repair or replace the boost pressure sensor
Check the boost pressure sensor and the corresponding circuit. (Refer to the boost pressure
NG
and/or the corresponding circuit.
sensor check procedure issued by the vehicle
manufacturer.)
OK
10
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 117
(10) Knocking, abnormal noise
Description
Abnormal combustion occurs, and a knocking sound is generated.
Possible Cause
• Engine
• Injector
• Glow control system
• Crankshaft position sensor
Clogged air cleaner element
1
Repair the glow control system.
Repair the glow control system. (Refer to the
glow control system check procedure issued by
NG
the vehicle manufacturer.)
OK
2
Repair or replace the crankshaft position sensor
Check the crankshaft position sensor. (Refer to
the crankshaft position sensor check procedure
NG
and/or the corresponding circuit.
issued by the vehicle manufacturer.)
OK
3
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
4
Check engine parts that may be a source of
abnormal combustion.
OK
Troubleshooting complete
Repair the engine.
NG
2– 118
Repair Section
(11) Poor fuel economy
Description
More fuel than normal is being consumed.
Possible Cause
• Engine
• Injector
• Supply pump
Clogged air cleaner element
1
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
2
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive cir-
NG
cuit.
cuit diagram issued by the vehicle manufacturer.)
OK
3
Check parts that may be a source of poor fuel
Repair the engine.
NG
economy.
OK
Troubleshooting complete
R
e
p
a
i r
S
e
c
t i o
n
2– 119
(12) Black Smoke
Description
Black smoke is being exhausted.
Possible Cause
• Injector
• Supply pump
• EGR system
• Engine ECU
• Electronic control throttle
• Rail pressure sensor
• Mass Air Flow (MAF) meter
• Boost pressure sensor
Clogged air cleaner element
1
Check for air cleaner clogging and/or damage.
Replace the air cleaner or repair the air duct.
NG
OK
2
Repair or replace the electronic control throttle
Check the electronic control throttle and the corresponding circuit. (Refer to the electronic con-
NG
and/or the corresponding circuit.
trol throttle check procedure issued by the
vehicle manufacturer.)
OK
3
Repair or replace the MAF meter and/or the cor-
Check the MAF meter and the corresponding
circuit. (Refer to the MAF meter check proce-
NG
responding circuit.
dure issued by the vehicle manufacturer.)
OK
4
Repair or replace the EGR system.
Check the Exhaust Gas Recirculation (EGR)
system. (Refer to the EGR system check proce-
NG
dure issued by the vehicle manufacturer.)
OK
5
Repair or replace the boost pressure sensor
Check the boost pressure sensor and the corresponding circuit. (Refer to the boost pressure
NG
and/or the corresponding circuit.
sensor check procedure issued by the vehicle
manufacturer.)
OK
6
Repair or replace the rail pressure sensor and
Check the rail pressure sensor and the corresponding circuit. (Refer to the rail pressure sensor check procedure issued by the vehicle
manufacturer.)
NG
the corresponding circuit.
2– 120
Repair Section
OK
7
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
8
Repair the engine ECU power supply.
Check the engine ECU power supply. (Refer to
the engine ECU power supply circuit diagram
NG
issued by the vehicle manufacturer.)
OK
9
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive circuit diagram issued by the vehicle manufacturer.)
OK
Troubleshooting complete
NG
cuit.
Repair Section
2– 121
(13) White smoke
Description
White smoke is being exhausted.
Possible Cause
• Fuel filter
• Injector
• Supply pump
• EGR system
• Engine ECU
• Electronic control throttle
• Rail pressure sensor
Clogged air cleaner element
1
Check the fuel filter.
Replace the fuel filter.
NG
OK
2
Check each injector. (Refer to the injector check
procedure issued by the vehicle manufacturer.)
Repair or replace the injector and/or the corre-
NG
sponding circuit.
OK
3
Repair or replace the EGR system.
Check the Exhaust Gas Recirculation (EGR)
system. (Refer to the EGR system check proce-
NG
dure issued by the vehicle manufacturer.)
OK
4
Repair or replace the supply pump and drive cir-
Check the supply pump and the supply pump
drive circuit. (Refer to the supply pump drive cir-
NG
cuit.
cuit diagram issued by the vehicle manufacturer.)
OK
5
Repair or replace the rail pressure sensor and
Check the rail pressure sensor and the corresponding circuit. (Refer to the rail pressure sen-
NG
the corresponding circuit.
sor check procedure issued by the vehicle
manufacturer.)
OK
6
Repair or replace the electronic control throttle
Check the electronic control throttle and the corresponding circuit. (Refer to the electronic control throttle check procedure issued by the
vehicle manufacturer.)
OK
Troubleshooting complete
NG
and/or the corresponding circuit.
2– 122
Repair Section
5.2 Other Malfunction Symptoms
Malfunctions caused by components other than the CRS
z There are occasions when a malfunction that appears to be generated by the CRS is actually caused by a different component or system. For instance, engine mechanical parts and the fuel system may cause malfunction symptoms identical to symptoms generated by the CRS. When troubleshooting, do not simply assume that the source of a malfunction
is the CRS. Consider all causes should be exhaustively considered while verifying the list below.
Malfunction
Faulty Item
Cause
Action
Symptom
Intake system
Fuel system
Insufficient
Clogged air cleaner element
Clean or replace the air cleaner element.
Air mixed with the fuel system
Perform fuel system air bleeding.
Faulty fuel filter
Replace the filter.
Insufficient fuel
Add fuel and perform fuel system air
bleeding.
Power
Engine
Improper fuel
Switch to the correct fuel.
Compression pressure abnormality
Refer to the engine repair manual.
Piston, cylinder liner and/or piston ring
Other
Overheat
Intake system
Clogged air cleaner element
Clean or replace the air cleaner element.
Insufficient fuel
Add fuel and perform fuel system air
bleeding.
Fuel system
Improper fuel
Replace the filter.
Fuel system clog
Clean the fuel system.
Air introduction through fuel system con- Tighten all connections.
nection points
Faulty starting
Electrical
tem
Fuel filter clog
Replace the fuel filter.
Loose injection piping connections
Tighten connecting nuts.
Faulty battery
Check the battery.
sys- Faulty starter wiring
Loose battery cables
Replace the starter wiring.
Tighten the battery terminal connections,
or replace the cables.
Electrical
sys- Faulty starter operation
Replace the starter assembly.
tem
Faulty glow plug system
Replace the glow plugs.
Lubrication
Excessive engine oil viscosity
Replace with oil of appropriate viscosity.
Burnt pistons
Replace the piston, piston ring and cylin-
system
Faulty starting
der liner.
Engine
Other
Burnt bearings
Replace the bearing and crankshaft.
Low compression pressure
Overhaul the engine.
Ring gear damage
Replace the ring gear and/or starter pinion gear.
Repair Section
Malfunction
Faulty Item
Cause
2– 123
Action
Symptom
Poor valve clearance
Adjust the valve clearance or replace the
bearing.
Poor valve seat contact
Faulty idling
Break in, or replace the valve and valve
seat.
Engine
Low coolant temperature
Perform warm-up operation.
Large difference in cylinder-to-cylinder Overhaul the engine.
compression pressure
Repair Section
2– 124
6. DIAGNOSIS CODES (DTC)
6.1 DTC Chart (Example)
DTC Structure
z P####: Powertrain-related (engine, drive system)
z U####: Network-related (vehicle communication)
DTC Assignment
z PO###: Determined by SAE/ISO
z P1###: Determined by manufacturer
z P2###: Determined by manufacturer
z P3###: Mixture of items determined by SAE/ISO and items determined by the vehicle manufacturer.
DTC Chart (example for HINO and TOYOTA vehicles)
z DTC codes that apply to the CRS are listed below (compatible with the DST-2.)
DTC
DTC Description
P0006
Fuel shutoff valve "A" control circuit low voltage
P0007
Fuel shutoff valve "A" control circuit high voltage
P0016
Crankshaft position sensor, cylinder recognition sensor correlation
P0030
A/F sensor heater control circuit
P0031
A/F sensor heater control circuit low voltage
P0032
A/F sensor heater control circuit high voltage
P0036
A/F sensor heater control circuit
P0037
A/F sensor heater control circuit low voltage
P0045
Turbo/supercharger control solenoid open circuit
P0049
Turbo/supercharger overspeed
P0087
Fuel/rail pressure too low
P0088
Fuel/rail pressure too high
P0093
Fuel system leak maximum quantity detection
P0095
Intake air temperature sensor 2, circuit related
P0097
Intake air temperature sensor 2 circuit low voltage
P0098
Intake air temperature sensor 2 circuit high voltage
P0100
Mass Air Flow (MAF) meter, circuit related
P0101
MAF meter circuit range/performance
P0102
MAF meter circuit low input
P0103
MAF meter circuit high input
P0105
Boost pressure sensor, circuit related
P0107
Boost pressure sensor circuit low input
P0108
Boost pressure sensor circuit high input
P0112
Boost pressure sensor 1 circuit low voltage
P0113
Boost pressure sensor 1 circuit high voltage
P0115
Coolant temperature sensor, circuit related
P0117
Coolant temperature sensor circuit low voltage
Repair Section
DTC
DTC Description
P0118
Coolant temperature sensor circuit high voltage
P0119
Coolant temperature sensor circuit intermittent operation
P0120
Accelerator position sensor, switch "A" circuit related
P0121
Accelerator position sensor switch "A" circuit range/performance
P0122
Accelerator position sensor switch "A" circuit low voltage
P0123
Accelerator position sensor switch "A" circuit high voltage
P0124
Accelerator position sensor switch "A" circuit intermittent operation
P0168
Fuel temperature too high
P0180
Fuel temperature sensor, "A" circuit related
P0181
Fuel temperature sensor "A" circuit range/performance
P0182
Fuel temperature sensor "A" circuit low voltage
P0183
Fuel temperature sensor "A" circuit high voltage
P0184
Fuel temperature sensor "A" circuit intermittent operation
P0185
Fuel temperature sensor, "B" circuit related
P0186
Fuel temperature sensor "B" circuit range/performance
P0187
Fuel temperature sensor "B" circuit low voltage
P0188
Fuel temperature sensor "B" circuit high voltage
P0189
Fuel temperature sensor, "B" circuit intermittent operation
P0190
Rail pressure sensor, circuit related
P0191
Rail pressure sensor circuit range/performance
P0192
Rail pressure sensor circuit low voltage
P0193
Rail pressure sensor circuit high voltage
P0194
Rail pressure sensor circuit intermittent operation
P0200
Injector open circuit
P0201
Injector open circuit- #1 cylinder
P0202
Injector open circuit- #2 cylinder
P0203
Injector open circuit- #3 cylinder
P0204
Injector open circuit- #4 cylinder
P0205
Injector open circuit- #5 cylinder
P0206
Injector open circuit- #6 cylinder
P0208
Injector open circuit- #8 cylinder
P0217
Engine overheat
P0218
Transmission overheat
P0219
Engine overrun
P0230
Fuel pump, primary circuit related
P0234
Turbo/supercharger overboost
P0237
Boost pressure sensor circuit low voltage
P0263
Cylinder correction quantity error- #1 cylinder
P0266
Cylinder correction quantity error- #2 cylinder
P0269
Cylinder correction quantity error- #3 cylinder
P0272
Cylinder correction quantity error- #4 cylinder
2– 125
Repair Section
2– 126
DTC
DTC Description
P0275
Cylinder correction quantity error- #5 cylinder
P0278
Cylinder correction quantity error- #6 cylinder
P0299
Turbo/supercharger supercharge deficiency
P0335
Crankshaft position sensor, "A" circuit related
P0339
Crankshaft position sensor "A" circuit intermittent operation
P0340
Cylinder recognition sensor, "A" circuit related
P0400
EGR flow volume abnormality
P0404
EGR control circuit range/performance
P0405
EGR sensor "A" circuit low voltage
P0406
EGR sensor "A" circuit high voltage
P0407
EGR sensor "B" circuit low voltage
P0408
EGR sensor "B" circuit high voltage
P0500
Vehicle speed sensor, "A" circuit related
P0501
Vehicle speed sensor "A" circuit range/performance
P0504
Brake switch "A", "B" correlation
P0510
Throttle position switch closed
P0524
Engine oil pressure too low
P0540
Intake air heater "A" circuit
P0544
Exhaust gas temperature sensor, circuit related
P0545
Exhaust gas temperature sensor circuit low voltage
P0546
Exhaust gas temperature sensor circuit high voltage
P0560
Battery voltage
P0605
Engine ECU internal malfunction
P0607
Engine ECU internal malfunction
P0611
EDU malfunction
P0617
Starter relay circuit high voltage
P0627
Fuel pump "A" open control circuit
P0686
Engine ECU power supply relay control circuit low voltage
P0704
Clutch switch input circuit abnormality
P0710
Transmission oil temperature sensor, "A" circuit related
P0715
Turbine speed sensor, "A" circuit related
P0753
Shift solenoid "A" actuation related
P0758
Shift solenoid "B" actuation related
P0850
Parking/neutral switch, input circuit related
P2002
Particulate Matter (PM) capture efficiency at or below specified value
P2031
Exhaust gas temperature sensor, circuit related
P2032
Exhaust gas temperature sensor circuit low voltage
P2033
Exhaust gas temperature sensor circuit high voltage
P2047
Exhaust gas fuel addition valve abnormality
P2120
Accelerator position sensor, switch "D" circuit related
P2121
Accelerator position sensor switch "D" circuit range/performance
Repair Section
DTC
DTC Description
P2122
Accelerator position sensor, switch "D" circuit low input
P2123
Accelerator position sensor, switch "D" circuit high input
P2125
Accelerator position sensor, switch "E" circuit related
P2127
Accelerator position sensor, switch "E" circuit low input
P2128
Accelerator position sensor, switch "E" circuit high input
P2138
Accelerator position sensor, switch "D"/"E" circuit voltage correlation
P2226
Atmospheric pressure sensor, circuit related
P2228
Atmospheric pressure sensor circuit low voltage
P2229
Atmospheric pressure sensor circuit high voltage
2– 127
2– 128
Repair Section
Published
: August 2004
Second Issu: September 2007
Edited and published by:
DENSO CORPORATION
Service Department
1-1 Showa-cho, Kariya, Aichi Prefecture, Japan
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