Diagnosis system for a motor vehicle

Diagnosis system for a motor vehicle
United States Patent [191
[11]
Patent Number:
4,996,643
Sakamoto et a1.
[45]
Date of Patent:
Feb. 26, 1991
[54] DIAGNOSIS SYSTEM FOR A MOTOR
[56]
References Cited
VEHICLE
us. PATENT DOCUMENTS
‘
4,527,424
[75] Inventors: Masanori Snkamoto; Kunihlro Abe;
[73] Assignee:
4,748,843
6/1988 Schiifer et
4.757.463
7/1988
4.926.330
5/1990 Abe et a1.
Fuji Jukogyo Kabushiki Kaisha,
........ .7 73/ 117 3
.... .. 364/5511“
364/424.03
1/1983 Japan .
Primary Examiner—Felix D. Gruber
Attorney, Agent, or Firm-Martin A. Farbcr
[57]
Feb‘ 2’ 1989
ABSTRACT
An electronic control system mounted on a motor vehi
cle has an identi?cation code representing the type of
Foreign Application Priority Data
Feb. 18. 1988 [JP]
.
Ballou et al.
FOREIGN PATENT DOCUMENTS
53-12343
.
[30]
73/119 A
364/551.0l
Tomoya Kobayashi, all of Tokyo,
[21] APPL N04 306,892
Flled:
Takahashi .. .
Japan
Tokyo, Japan
[22]
7/1985
4,694,408 9/1987 Zaleski
the vehicle. A control unit provided in a diagnosis de
vice selects a diagnosis program for diagnosing the
Japan .............................. .. 63-036422
control system from a plurality of diagnosis programs in
[52]
Int. Cl.5 ................... .. 601M 15/00; F02D 41/26;
FOZP 17/00
US. Cl. ............................ .. “M42433; 73/ 117.2;
accordance with the identi?cation code. A keyboard is
provided for inputting another identi?cation code- The
control unit responds to the other identi?cation code
input with the keyboard for selecting the diagnosis
[58]
Field of Search .................... .. 364/4310], 551.01;
[51]
364/43L0l; 364/5510]
program.
73/116, 117.2, 117.3, 119 R, 119 A
SENSDRS
AND
5 Claims, 6 Drawing Sheets
25
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COMMUNICATION
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TYPE 2005
INTERPRETING
DETERMINING
MEANS
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ACTUATURS
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TABLE
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US. Patent
Feb. 26, 1991
Sheet 5 0f 6
4,996,643
J38
TB2
'
TB1 f
00
MODEL YEAR PROGRAM
01
BATTERY VOLTAGE PROGRAM
O2
VEHICLE sPEEO sENsOR
OUTPUT DATA (m/h) PROGRAM
VEHICLE SPEED sENsOR
03
OuTPuT DATA (km/h) PROGRAM
0
4
ENGINE sPEEO sENsOR
DATA PROJGgAM
ENGINE sPEEO sENsOR
05
06
OATA PROGRAM
GOOLANT TEMPERATURE
sENsOR OUTPUT
OATA (deg?) PROGRAM
.
CDDLANT TEMPERATURE
07
sENsOR OUTPUT
OATA (degfc) PROGRAM
09
AIR FLOW METER
OUTPUT DATA PROGRAM
11
THROTTLE POSITION sENsOR
OuTPuT DATA PROGRAM
FUEL INJECTION PuLsE
WIDTH PROGRAM
12
OORREOTION COEFFICIENT
17
OF AIR FUEL RATIO
GONTROL PROGRAM BASED ON
02 SENSOR OUTPUT OATA
A1
DNHDFF sIGNAL CHECK
PROGRAM FOR LEDS
FIG/4
US. Patent
Feb. 26, 1991
Sheet 6 6r 6
4,996,643
FIGS
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4,996,643
DIAGNOSIS SYSTEM. FOR A MOTOR VEHICLE
BACKGROUND OF THE INVENTION
The present invention relates to a diagnosis system
for a motor vehicle.
Recently, a motor vehicle has been equipped with an
electronic control system for controlling various com
ponents of an engine, such as fuel injectors, thereby
improving driveability, exhaust gas emission, fuel con
sumption and engine power. The electronic control
system controls the components based on information
represented by output signals from various sensors for
detecting engine operating conditions. Accordingly, if
malfunctions of components and sensors occur, the
engine does not properly operate.
However, because of the complexity of the electronic
2
The other objects and features of this invention will
become understood from the following description with
reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustration of a diagnosis sys
tem according to the present invention;
FIGS. 2a and 2b show a block diagram of the system;
FIG. 3 is a block diagram showing a main part of the
20, system;
FIG. 4 is an illustration showing control programs for
various vehicle type codes stored in a ROM; and
FIG. 5 is a flowchart showing an operation of the
system.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENT
Referring to FIG. 1, an automobile 1 is equipped with
control system, it is dif?cult to immediately ?nd out
trouble. Accordingly, a trouble diagnosis device for 20 an electronic control system 2 for controlling various
components of an engine E. The electronic control
easily checking the electronic control system should be
system 2 is connected to an external connector 24. A
provided in an auto shop. The electronic control system
portable diagnosis device 25 comprising a microcom
has a memory and a communication system to be con
puter is housed in a case 250 and has a connector 26, to
nected to the trouble diagnosis device.
Since the address of the memory and the communica 25 which the connector 24 of the system 2 is connected
through an adapter harness 27.
tion system differ with different types of motor vehi
The diagnosis device 25 has a power switch SW4, a
cles, an identi?cation code of a type of motor vehicle is
liquid crystal display 31, an indicator section 30 consist
stored in the memory. The diagnosis device discrimi
ing of a plurality of LED indicators, and a keyboard 32.
nates the vehicle type based on the identi?cation code.
30 A connector 33 is provided for connecting a detachable
Japanese patent application Laid-Open 58-12848 dis
closes a diagnosis system in which an exclusive check
memory cartridge 34.
Referring to FIGS. 2a and 2b, the electronic control
system 2 comprises a central processor unit (CPU) 3, a
various sensors and actuators. However, the checking
random access memory (RAM) 4, a read only memory
device is provided for diagnosing only designated spe
(ROM)
5 an input interface 6,,and an output interface 7.
35
ci?c types of motor vehicle.
These units, namely the CPU 3, RAM 4, ROM 5, and
Although, a diagnosis system can store a plurality of
the input and output interfaces 6 and 7 are connected to
control programs for diagnosing various types of motor
each other through a bus line 8. Programs and data for
vehicles in a memory, control programs for all types of
controlling the engine and ?xed data such as the type of
motor vehicle can not be stored in the memory.
the vehicle are stored in the ROM 5. Power is supplied
On the other hand, there is a case where diagnosis can
to the CPU 3, input and output interfaces 6 and 7, and
be performed with a program for another type of vehi
driver 18 from a source BV through a contact 430 of a
cle. However, since the identi?cation code is different
power relay 43 and a constant voltage circuit 16. A
from the other one, the program cannot be used.
relay coil 43b of the relay 43 is connected to the source
BV through an ignition terminal 16 of an ignition
SUMMARY OF THE INVENTION
switch 45.
The object of the present invention is to provide a
The input interface 6 is applied with a coolant tem
diagnosis system which may diagnose the electronic
perature signal Tw from a coolant temperature sensor 9,
control system with common programs, even if the
an air-fuel ratio feedback signal 01 from an 0; sensor 10,
identi?cation code does not coincide with the code of
an intake~air quantity signal Q from an intake manifold
the programs.
quantity sensor 11, a vehicle speed signal S from a vehi
According to the present invention, there is provided
cle speed sensor 13, a throttle valve opening degree
a system for diagnosing an electronic control system
signal - from a throttle position sensor 15, an engine
mounted on a motor vehicle, the electronic control
speed signal N from an engine speed sensor 17, an air
system having an identi?cation code representing the
conditioner operating signal AC from an air conditioner
type of the vehicle, a diagnosis device including a com
switch SW1, an idling signal ID from an idle switch
puter having a central processing unit and a memory,
SW2, and a neutral positioning signal NT from a neutral
the memory storing a plurality of diagnosis programs
switch SW3 in a transmission.
for diagnosing the electronic control system, and dis
These signals are stored in the RAM 4 after process
play means, connecting means connecting the computer
ing data in accordance with the program stored in the
to the electronic control system, a control unit provided
ROM 5. The CPU 3 produces respective control sig
in the diagnosis device for selecting a diagnosis program
nals, which are applied to the driver 18 through the
ing device is provided for diagnosing operations of
for diagnosing the control system from the diagnosis
output interface 7. The driver 18 produces signals for
programs in accordance with the identi?cation code,
controlling a kicltdown solenoid 12 of a kickdown
input means for inputting another identi?cation code, 65 switch, a fuel pump relay 14, a canister controller 19 of
the control unit being arranged to respond to the other
a fuel-vapor emission control system, an EGR (exhaust
identi?cation code input with the input means for se
lecting the diagnosis program.
gas recirculation system) actuator 20, an idling control
actuator 21, ignition coils 22 and fuel injectors 23.
3
4,996,643
The driver 18 further applies signals to D-check
lamps 23a and U-check lamps 23b. The D-check lamps
23a are provided in the electronic control system 2 for
indicating an abnormality in the system 2. When an
abnormality is detected in the system 2 by a self-diagno
sis function, a corresponding trouble code is read out
4
A vehicle type code determining means 52 selects a
control program from the tables TB! to T8,, stored in
the ROM 41 in the memory cartridge 34 in accordance
with an identi?cation code stored in the ROM 5 in the
control system 2. A data communication means 53 re
trieves a designated range corresponding to the desig
from the ROM 5 so as to turn on or ?ash a plurality of
nated mode of the selected control program in accor
lamps 23a, thereby indicating the trouble code. The
dance with a mode signal from the keyboard interpret
ing means 51 based on the designated mode input by the
keyboard 32. In accordance with a diagnosis program
stored in the designated range, the data communication
means 53 produces a data demand signal TX which is
applied to the control system 2 and receives a data
signal RX fed from the control system 2. A data con
U-check lamps 23b are provided on a dashboard of the
vehicle so as to warn the driver of the trouble detected
by the self-diagnosis function.
The diagnosis device 25 has a control unit 28 and a
power supply source 29. The control unit 28 comprises
a CPU 36, a RAM 37, input/output (I/0) ports 39 and
40, and a timer 38. These elements are connected to
verting means 54 converts the data received at the data
each other through a bus line 35. A clock pulse genera
tor 42 is provided in the timer 38 for generating syn~
communication means 53 into decimal digits. A display
driving means 55 produces a signal in accordance with
the output of the data converting means 54 for driving
chronizing pulses.
Inputs of the I/0 port 40 are connected to the output
interface 7 of the control system 2 through connectors 24 and 26 and harness 27 so as to receive output signals
of the sensors and switches. Outputs of the port 40 are
connected to the indicator section 30. Inputs of the U0
port 39 are connected to the keyboard 32 for being
applied with a mode select signal dependent on the
operation of the keyboard, and to the output interface 7.
Outputs of the port 39 are connected to the input inter
face 6 and the display 31. The power source 29 for
supplying the power to the CPU 36 and U0 ports 39 and
40 is connected to the source BV through the power
switch SW4.
The indicator section 30 has a plurality of LEDs Dito
the display 31.
The operation of the system is described hereinafter
with reference to the ?owchart of FIG. 5. The diagno
sis device 25 is connected to the electronic control
system 2 through the connectors 24, 26 and harness 27.
The engine is started, and the following diagnosis pro
gram is performed under the running condition of the
engine.
The power switch SW4 is turned on at a step S101.
At a step S102, initialization of the control unit 28 is
performed. At a step S103, an identification code de
mand signal from the data communication means 53 is
applied to the system 2. In response to the code demand
signal, the control system 2 derives an identi?cation
code signal stored in the ROM 5, which is fed to the
D10 arranged in two rows. The liquid crystal display 31
has two rows of liquid crystal cells, each row consisting 35 communication means 53 at a step S104.
of ?ve pairs of liquid crystal cells. Each pair of cells
corresponds to the respective LEDs D1 to D10. Input
At a step S105, in accordance with the received iden
ti?cation code, the vehicle type code determining
ting and outputting conditions of the switches and sen
means 52 retrieves a control program if it exists for the
sors are indicated by intermittently turning on the
vehicle type code, from tables TBl to TBn in the ROM
LEDs D1 to D10 in accordance with a selected checking 40 41 and determines whether the control program corre
mode.
sponding to the vehicle type identi?cation code exists
On the liquid crystal cells of the display 31, the se
or not. If the corresponding control program exists, the
lected switches and sensors are indicated by identifica
diagnosis program goes to a step 5106. If the corre
tion codes. The display 31 is also capable of displaying
sponding control program is not derived, an error is
measured values such as output voltages and pulse 45 displayed on the display 31 and the program proceeds
widths of signals from the sensors and actuators depen
to a step $107.
dent on the selected mode as shown in FIG. 1.
The memory cartridge 34 selected for diagnosing the
presented control system 2 is connected to the diagnosis
The diagnostician refers to a service manual to find a
control program which has the same content as the
program of the corresponding type code and inputs the
device 25 through the connector 33. A ROM 41 pro
type code of the derived program with the keyboard 32
vided in the memory cartridge 34 stores control pro
(step S107). The vehicle type code determining means
grams corresponding to the identi?cation code of the
52 treats the type code as a code for the control system
vehicle and ?xed data.
2, and the program proceeds to the step 8106.
Referring to FIG. 4, the ROM 41 stores, as ?xed data,
At step S106, the type code input at the step S105 or
a plurality of tables T131 to TB", each having a control $5 at the step S107 is stored in a predetermined address of
program for the speci?c type of the vehicle. In the
the RAM 37.
ROM, various data for the type of the vehicle, such as
At a step S108, the type code determining means 52
a memory address, communication system and diagno
selects a control program corresponding to the type
sis programs are stored.
code from tables TBl to TBn (for example from the
When a desired diagnosing mode is input by operat 60 table TBl). Consequently, the corresponding control
ing the keyboard 32, a designated diagnosis program is
program for the control system 2 to be diagnosed is
selected from the control programs stored in the tables
determined and a diagnosis routine is performed in ac
and the diagnosis according to the diagnosis program is
cordance with the program.
performed.
A diagnostician operates the keyboard 32 to perform
Referring to FIG. 3 showing the control unit 28, a 65 the diagnosis of the engine. For example, in order to
keyboard interpreting means 51 is provided for inter
measure the coolant temperature, a mode code for the
preting a designated mode and other input by operating
the keyboard 32.
coolant temperature (for example F—+0—>7—>ENT) is
input by operating the keyboard 32 at a step S109.
4,996,643
5
,
The input mode is read by the CPU 36 and temporar
ily stored in the RAM 37. Thereafter, the mode is read
and interpreted in the keyboard interpreting means 51.
6
tively, for retrieving a corresponding of said pro
grams for the diagnosing.
2. A system for diagnosing an electronic control sys
A program according to a mode 07 in the table TBI
representing a coolant temperature sensor output data
program (FIG. 4) is read out at a step S110. At a step
cle, the electronic control system containing therein an
identi?cation code representing type of the vehicle, the
111, a corresponding data demand signal TX is applied
diagnosing system comprising
tem, which includes sensors, mounted on a motor vehi
to the system 2. At a step 5112, data signal RX repre~
senting a coolant temperature is applied to the means 53
from the control system 2. At a step 113, the received
a diagnosis device including a computer having a
central processing unit and a memory, the memory
having a plurality of diagnosis programs for diag
nosing the electronic control system, and display
means for indicating results of diagnosis;
binary digit is converted into a decimal digit represent
ing the coolant temperature in the means 54.
The driving means 55 produces data which is applied
to the display 31. At a step 8114, a measured value of
the coolant temperature, for example, +14 deg C. rep
15
resenting the temperature, an abbreviation mark TW of
coolant temperature, and the input mode indiction F07
are displayed on the display 31 as shown in FIG. 1.
Thus, the diagnostician can diagnose the items about the
20
coolant temperature.
In order to perform other diagnosis items, the key
board operation is performed and the operations a?er
step S109 are repeated.
.In accordance with the present invention, since a
control program either in accordance with a vehicle
type code of the electronic control system and a vehicle
connecting means for connecting the computer to the
electronic control system;
the central processing unit for determining if there
exists a corresponding diagnosis program corre
sponding to the identi?cation code for diagnosing
said electronic control system among said plurality
of diagnosis programs in said memory;
the diagnosis device includes input means for manu
ally inputting another identi?cation code corre
sponding to another suitable diagnosis program of
said plurality of diagnosis programs for diagnosing
25
type code input by operating the keyboard is used,
various types of vehicles can be diagnosed.
said electronic control system in the event said
?rst-mentioned corresponding diagnosis program
is determined by said central processing unit not to
exist among said plurality of diagnosis programs in
While the presently preferred embodiment of the
said memory; and
the central processing unit for responding to said
present invention has been shown and described, it is to
be understood that this disclosure is for the purpose of
system or to said another identi?cation code input
illustration and that various changes and modi?cations
may be made without departing from the scope of the
invention as set forth in the appended claims.
35
What is claimed is:
1. In a diagnosis system for an electronic control
system mounted on a motor vehicle having sensing
identi?cation code from said electronic control
manually for selecting for the diagnosing said diag
nosis program corresponding to said identi?cation
code from said electronic control system or said
another suitable diagnosis program corresponding
to said another identi?cation code, respectively.
3. The system according to claim 2, wherein
said input means is a keyboard.
means for detecting operating conditions of the vehicle
and for producing input data, and means for storing an 40 4. A method for diagnosing an electronic control
identi?cation code corresponding to type of the vehicle
system which includes sensors mounted on a motor
and for storing the input data from said sensing means
vehicle, the electronic control system containing an
and for providing control data for controlling the vehi
identi?cation code representing type of the vehicle, the
cle, the diagnosis system being responsive to at least one
diagnosing system comprising a diagnosis device in
of said data for diagnosing said at least one of said data 45 cluding a computer having a central processing unit and
and for providing diagnosis data, the diagnosis system
a memory, the memory having a plurality of diagnosis
comprising display means for displaying said diagnosis
programs for diagnosing the electronic control system,
data, and a keyboard for inputting a code into said diag
and display means for indicating results of diagnosis, the
nosis system and for producing a corresponding code
method comprising the steps of
signal, a detachable memory cartridge detachably con
detecting an identi?cation code signal corresponding
nected to said diagnosis system for storing a plurality of ,
to the vehicle type and to the corresponding identi
programs to diagnose said at least one data, connecting
?cation code from the memory in the electronic
means for connecting said diagnosis system with said
control system;
electronic control system and said detachable memory
the computer determining if a diagnosis program
cartridge which have different types of data signals 55
exists or does not exist in said plurality of diagnosis
being transmitted in response to a demand signal, the
programs corresponding to said identi?cation code
improvement in the diagnosis system which comprises:
data converting means responsive to said diagnosis
data for converting said diagnosis data and for
producing a corresponding driving signal for dis
signal;
if said diagnosis program does not exist, selecting and
inputting another identi?cation code signal corre
sponding to another suitable diagnosis program of
play of the converted diagnosis data on said display
said plurality of diagnosis programs for diagnosing
means;
said electronic control system; and
keyboard interpreting means responsive to the code
signal corresponding to a vehicle type code input
ted into said keyboard for generating a correspond 65
ing type code signal; and
'
type code determining means responsive to said type
code signal and said identi?cation code, respec
the computer selecting for the diagnosing the diagno
sis program of said plurality of diagnosis programs
corresponding to said identi?cation code signal or
corresponding to said another identi?cation code
signal, respectively, for the diagnosing of the elec
tronic control system.
7
4,996,643
5. The method according to claim 4, further compris
ing the steps of
corresponding to the vehicle type and identi?ca
'
tion code from the memory in the electronic con
trol system occurs in response to said identi?cation
initially applying an identi?cation code demand sig~
nal to the electronic control system, and wherein
code demand signal.
said step of detecting the identi?cation code signal 5
l0
15
20
25
30
35
45
50
55
65
i
I
i
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