13C-1
DIESEL FUEL
<4M4>
CONTENTS
GENERAL INFORMATION 2...................
SERVICE SPECIFICATIONS 3.................
SEALANT 3..................................
SPECIAL TOOLS 4...........................
TROUBLESHOOTING 5.......................
ON-VEHICLE SERVICE 42...................
Injection Timing Check and Adjustment 42.........
Idle Speed Check and Adjustment 42.............
Accelerator Pedal Position Sensor (APS)
Adjustment 42.................................
Control Relay Continuity Check 43................
Accelerator Pedal Position Sensor (APS) Check 43.Idle Switch Check 43...........................
Boost Air Temperature Sensor (Intake Air
Temperature Sensor) Check 44..................
Engine Coolant Temperature Sensor Check 44.....
Evacuation of Water from Fuel Filter 45...........
Fuel Filter Cartridge Replacement 45.............
Evacuation of Air from Fuel Line 45...............
Fuel Injection Pump Check 46...................
Intake Air Restriction Equipment Check 48.........
Injection Nozzle Check and Adjustment 49.........
INJECTION NOZZLE 50......................
INJECTION PUMP 56........................
ENGINE-ECU 59............................
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DIESEL FUEL <4M4> -General Information13C-2
GENERAL INFORMATION
The electronically-controlled fuel injection system consists of sensors which detect the condition of the
diesel engine, an engine-ECU which controls the system based on signals from these sensors, and actuators
which operate according to control commands from the engine-ECU.
The engine-ECU carries out operations such as fuel injection rate control, fuel injection timing control
and idle up control. In addition, the engine-ECU is equipped with several self-diagnosis functions which
make troubleshooting easier in the event that a problem develops.
FUEL INJECTION RATE CONTROL
The fuel injection completion timing is controlled by means of a solenoid-type spill valve to ensure that
the optimum amount of fuel is supplied to the engine in accordance with gradual changes in the engine
running condition.
Before fuel injection starts, the solenoid-type spill valve is on (energized), so that the valve is closed.
As the plunger turns and rises, fuel is sent out under pressure, and when the fuel flow rate reaches
the target value for fuel injection, the solenoid-type spill valve turns off. When the solenoid-type spill
valve turns off, the fuel under high pressure inside the plunger is leaked out into the pump chamber
and fuel injection is completed.
FUEL INJECTION TIMING CONTROL
The position of the injection pump timer piston is controlled so that fuel injection is carried out at the
optimum timing in accordance with the engine running condition.
The timer piston position is determined by duty control of the timing control solenoid valve which is located
in the line between the high-pressure chamber and the low-pressure chamber of the timer piston.
The fuel injection timing is advanced by increasing the control duty of the timing control solenoid valve.
IDLE SPEED CONTROL
Controlling the fuel injection rate in accordance with the engine running condition maintains the idle speed
at the optimum condition.
SELF-DIAGNOSIS FUNCTION
DWhen an abnormality is detected in any of the sensors or actuators, the engine warning lamp illuminates
to warn the driver.
DWhen an abnormality is detected in any of the sensors or actuators, a diagnosis code number
corresponding to the problem which occurred is output.
DThe RAM data relating to the sensors and actuators which is stored in the engine-ECU can be read
using the MUT-II. In addition, the actuators can be force-driven under certain conditions.
OTHER CONTROL FUNCTIONS
1. Power Supply Control
When the ignition switch is turned to ON, the relay turns on and power is supplied to components
such as the timing control solenoid valve.
2. Intake Air Throttle Control
When the engine is idling after having warmed up, the throttle valve is half opened to restrict the
amount of intake air in order to reduce vibration and noise.
3. A/C Relay Control
Turns the compressor clutch of the A/C ON and OFF
4. Fan motor relay control
The radiator fan and condenser fan operating speeds are controlled in accordance with the engine
coolant temperature and the vehicle speed.
5. Glow Control
Refer to GROUP 16.
6. EGR Control
Refer to GROUP 17.
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DIESEL FUEL <4M4> -Troubleshooting13C-10
Code No. 13 Barometric pressure sensor systemProbable cause
Range of Check
DIgnition switch: ON, except for duringenginecranking
Set Conditions
DThe sensor output voltage is for 3 seconds is 4.5V or higher (the barometric
pressure is approximately 120 kPa or over).
or
DThe sensor output voltage is for 3 seconds is 1.5V or lower (the barometric
pressure is approximately 33 kPa or under).Engine-ECU inoperative
Replace the engine-ECU.NGCheck the trouble symptoms.
Code No. 14 Fuel temperature sensor systemProbable cause
Range of Check
DIgnition switch: ON, except for duringenginecranking
Set Conditions
DThe sensor output voltage for 3 seconds is 0.2V or higher (the fuel
temperature is approximately 120°C or higher).
or
DThe sensor output voltage for 3 seconds is 4.6V or lower (the fuel
temperature is approximately 50°C or lower).DFuel temperature sensor inoperative
DFuel temperature sensoropencircuit, short circuit,
or connector contact inoperative
DEngine-ECU inoperative
OK
Measure at B-38 fuel temperature sensor
connector
DDisconnect the connector and measure at
the harness side.
DVoltage between 11 and the earth
(Ignition switch: ON)
OK:
4.5 - 5.5 V
DContinuity between 7 and the earth
OK:
ContinuityNGCheck the following connectors:
D-112, D-113NG
Repair
OK
OK
Check the harness between the
engine-ECU and the fuel temperature
sensor connector.Repair
NG
Check the trouble symptoms.
Replace the engine-ECU.NG
Replace the engine-ECU.OKNG
Replace the injection pump.
OK
Repair
Check the following connector:
B-38
NG
NGCheck the trouble symptoms.
Fuel temperature sensor check (Refer to
P.13C-47.)
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DIESEL FUEL <4M4> -Troubleshooting13C-20
Code No. 43 Timing control valve systemProbable cause
Range of Check
DEngine coolant temperature 80_C or higher and the engine running
Set Conditions
DTarget value minus actual value is 1 V or more.DTiming controlvalve inoperative
DTiming controlvalveopencircuit, short circuit, or
connector contact inoperative
DEngine-ECU inoperative
OK
OK
Check and repair the harness between the
control relay and the injectionpump
assembly connector.
Timing controlvalve check (Refer to
P.13C-40.)
Replace the engine-ECU. OK
RepairCheck the following connector:
D-110
Check the trouble symptoms.NG NG NG
Check the following connector:
B-38NG
Repair
OK
Check the trouble symptoms.
NG
NGMeasure at D-110 engine-ECU connector.
DDisconnect the connector and measure at
the harness side.
DVoltage between 3 and the earth
(Ignition switch: ON)
OK:
System voltageOK
Measure at B-38 injectionpumpassembly
connector.
DDisconnect the connector and measure at
the harness side.
DVoltage between 5 and the earth
(Ignition switch: ON)
OK:
System voltage
Replace injection pumpassembly.
Check and repair the harness between the
engine-ECU and the injection pump
assembly connector.
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DIESEL FUEL <4M4> -Troubleshooting13C-21
Code No. 46 Injection correction ROM systemProbable cause
Range of Check
DIgnition switch: ON
Set Conditions
DWhen communication failsDInjection correction ROM inoperative
DEngine-ECU inoperative
Repair
OK
Replace the engine-ECU. OK
RepairCheck the following connector:
B-37
Check the trouble symptoms.NG NG
Check the following connectors:
D-112, D-113
NG
Repair
OK
Check the trouble symptoms.
NG
Measure at B-37 injection correction ROM
connector.
DDisconnect the connector and measure at
the harness side.
DVoltage between 3 and the earth
(Ignition switch: ON)
OK:
4.5 - 5.5 V
DContinuity between 2 and the earth
OK:
Continuity
Check and repair the harness between the
engine-ECU and the injection correction
ROM connector.
OK
Replace the engine-ECU.NG
Code No. 48 GE actuator (in the middle of control sleeve
position sensor inoperative) systemProbable cause
Range of Check
DIgnition switch: ON
Set Conditions
DTarget value minus actual value is 1 V or more.DControl sleeve position sensor inoperative
DGE actuator inoperative
DControl sleeve position sensoropencircuit, short
circuit, or connector contact inoperative
DEngine-ECU inoperative
OK
OK
Check and repair the harness between the
control relay and the injectionpump
assembly connector.
GE actuator check (Refer to P.13C-46.)
Replace the engine-ECU. OK
RepairCheck the following connector:
D-110
Check the trouble symptoms.NGNG NG
Check the following connector:
B-38NG
Repair
OK
Check the trouble symptoms.
NG
NGMeasure at D-110 engine-ECU connector
DDisconnect the connector and measure at
the harness side.
DVoltage between 1 and the earth
(Ignition switch: ON)
OK:
System voltageOK
Measure at B-38 injectionpumpassembly
connector.
DDisconnect the connector and measure at
the harness side.
DVoltage between 6 and the earth
(Ignition switch: ON)
OK:
System voltage
Replace injection pumpassembly.
Check and repair the harness between the
control relay and the injectionpump
assembly connector.
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DIESEL FUEL <4M4> -Troubleshooting13C-26
Inspection procedure 5
No initial combustion (unable to start)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
glow system, and power supply system.DControl system inoperative
DInjection pump inoperative
DGlow system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-30, 37.)OKCheck the following items in order:
DGlow plug, glowplugrelay
DBattery
DInjection nozzle
DInjection pump
DCompression pressure
DExistence of mixing foreign objects (water, kerosene) with
the fuel
Inspection procedure 6
Starting performance is bad when the engine is cold
(unable to start)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
fuel system, intake system, and glow system.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DIntake system inoperative
DGlow system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37)OKInspect the following items in order:
DGlow plug, glowplugrelay
DInjection nozzle, fuel filter
DThrottle body assembly
DExistence of starter switch signal input
DEngine oil
DInjection pump
DExistence of mixing foreign objects (water, kerosene) with
the fuel
Inspection procedure 7
Starting performance is bad regardless of whether the
engine is hot or cold (unable to start)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
fuel system, and intake system.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DIntake system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DInjection nozzle, fuel filter
DThrottle body
DCompression pressure
DInjection pump
DExistence of mixing foreign objects (water, kerosene) with
the fuel
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DIESEL FUEL <4M4> -Troubleshooting13C-27
Inspection procedure 8
Low idling speed when the engine is cold (improper
idling speed)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
and fuel system.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DInjection pump
DFuel filter
Inspection procedure 9
High idling speed (improper idling speed)
Probable cause
Probable causes can be found in troubles with control system and injection
pump.DControl system inoperative
DInjection pump inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DInjection pump
DStarter switch signal
Inspection procedure 10
Low idling speed (improper idling speed)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
and fuel.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DInjection nozzle
DInjection pump
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DIESEL FUEL <4M4> -Troubleshooting13C-28
Inspection procedure 11
Idling instable (rough idling, hunting)
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
fuel system, glow system, intake system, and EGR system.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DIntake system inoperative
DGlow system inoperative
DEGR system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DGlow plug, glowplugrelay
DEGR system
DInjection nozzle
DCompression pressure
DValve clearance
DThrottle body assembly
DInjection timing
DFuel line bleeding
DInjection pump
Inspection procedure 12
The engine stalls after running for a while.
Probable cause
Probable causes can be found in troubles with control system, injectionpump,
fuel system, and intake system.DControl system inoperative
DInjection pump inoperative
DFuel system inoperative
DIntake system inoperative
DEngine-ECU inoperative
NG
Repair
MUT-
IISelf-Diag code
Is a diagnosis code output?YESInspection chart for diagnosis codes (Refer to P.13C-7.)
NO
Conduct MUT-IIData list check and an actuator test. (Refer
to P.13C-32, 37.)OKInspect the following items in order:
DThrottle body assembly
DFuel filter
DInjection pump
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