2000 MITSUBISHI MONTERO Service Repair Manual

DIESEL FUEL <4M4> -Troubleshooting13C-6
FAIL-SAFE, BACKUP FUNCTIONS
When abnormalities in the major sensors are detected by diagnosis functions, pre-set control logic operates
to maintain a safe driving condition for the vehicle.
Diagnosis itemControl features in malfunction
Accelerator pedal position sensorD
Accelerator pedal released (idle switch ON)
Acceleration opening degree = 0%
D
Accelerator pedal applied (idle switchOFF)
Engine controlled at low speed
Acceleration opening degree = 20% fixed
Idle switchD
Void idling speed control.
D
Void cruise control.
Engine speed sensorD
Engine controlled at low speed
D
Void cruise control.
Boost air temperature sensorMaintain the intake air temperature at 50_
C.
Vehicle speed sensorD
Void idling speed control.
D
Void cruise control.
Engine coolant temperature sensorMaintain the engine coolant temperature at 80_
C.
Control sleeve position sensorD
Engine controlled at low speed
D
Void cruise control.
Timer piston position sensorD
Injection timing stabilizing control
D
Void cruise control.
Barometric pressure sensor (ECU
built-in)Keep the barometric pressure at 101 kPa.
Fuel temperature sensorMaintain the fuel temperature at 50_
C.
Boost pressure sensorKeep the boost pressure as barometric pressure (101 kPa).
Injection correction ROMVoid correction.
GE actuatorD
Engine controlled at low speed
D
Void cruise control.
Over boostVoid cruise control.
Timing control valveD
Injection timing stabilizing control
D
Void cruise control.


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DIESEL FUEL <4M4> -Troubleshooting13C-7
INSPECTION CHART FOR DIAGNOSIS CODES
Code No.Diagnosis itemReference
page
11Accelerator pedal position sensor (main) system13C-8
12*Boost pressure sensor system13C-9
13Barometric pressure sensor (ECU built-in) system13C-10
14Fuel temperature sensor system13C-10
15Engine coolant temperature sensor system13C-11
16Boost air temperature sensor system13C-11
17Vehicle speed sensor system13C-12
18Engine speed sensor (backup) system13C-13
21Engine speed sensor system13C-14
23Idle switch (accelerator pedal position sensor built-in) system13C-15
25*Timer piston position sensor system13C-16
26*Control sleeve position sensor system13C-17
27Accelerator pedal position sensor (sub) system13C-18
41*Main throttle solenoid valve system13C-19
43Timing control valve system13C-20
46Injection correction ROM system13C-21
48*GE actuator (in the middle of control sleeve position sensor inoperative) system13C-21
49*Over boost (turbocharger waste gate malfunction)13C-22
54Immobilizer system13C-22
Caution
If the the above-mentioned diagnosis code number with the asterisks can be displayed along with
another code number in parentheses simultaneously, check the other code number before replacing
the engine-ECU.
12 (41, 49), 26 (48), 25 (43), 41 (12, 49), 48 (26), 49 (12, 41)


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DIESEL FUEL <4M4> -Troubleshooting13C-8
INSPECTION PROCEDURE FOR DIAGNOSIS CODE
Code No. 11 Accelerator pedal position sensor systemProbable cause
Range of Check
DIgnition switch: ON, acceleratorpedal positionsensor (sub) operative, except
for during enginecranking
Set Conditions
DOutput voltage of accelerator pedal positionsensor (sub) for one second is
0.2 V or higher and lower than 2.5V. Output voltage of acceleratorpedal
position sensor (main) for one second is 4.5V or higher, or lower than 0.2V.
Range of Check
DIgnition switch:ON, except for duringenginecranking
Set Conditions
DThe output voltage of accelerator pedal positionsensor (main and sub) for
0.2 second is 0.2V or higher, or lower than 4.5V and the difference in
sensor output voltage between themain and sub is 1V or higher, or idle
switch:ON, and sensormain output voltage is 1.875V or higher.DAcceleratorpedal positionsensor inoperative
DAcceleratorpedal positionsensoropencircuit,
short circuit, or connector contact inoperative
DEngine-ECU inoperative
OK
OK
Measure at D-135 acceleratorpedal position
sensor connector
DDisconnect the connector and measure
at the harness side.
DVoltage between 2 and earth
(Ignition switch: ON)
OK:
4.5 - 5.5 V
DContinuity between 1 and earth
OK:
ContinuityNGCheck the following connector:
D-113NG
Repair
OK
OKRepair
NGAcceleratorpedal positionsensor check
(Refer to P.13C-37.)Replace
Check the trouble symptoms.
Replace the engine-ECU.NG
Check the trouble symptoms.
NG
Replace the engine-ECU.
NG
RepairCheck the following connectors:
D-113, D-135
OK NG
NG
Check the following connector:
D-113NG
Repair
OK
Check the harness between the
engine-ECU and the accelerator pedal
position sensor connector.
Check the trouble symptoms.
OK
Measure at D-113 engine-ECU connector
DConnect the connector.
DVoltage between 84 and the earth
(Ignition switch: ON)
OK:
0.9 - 1.1 V
(Throttle leveridling position)
4.1 V or higher
(Throttle lever fullyopened position)
Check the harness between the
engine-ECU and the accelerator pedal
position sensor connector.


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DIESEL FUEL <4M4> -Troubleshooting13C-9
Code No. 12 Boost pressure sensor (boost sensor)
systemProbable cause
Range of Check
DIgnition switch: ON, except for duringenginecranking
Set Conditions
DSensor output voltage for one second is 4.5 Vor higher
(boost pressure is approximately 306.7kPa).
or
DSensor output voltage for one second is 0.2 Vor lower
(boost pressure is approximately 20kPa or lower)
Range of Check
DEngine speed is 1600 r/min or higher and the accelerationopening degree is
60% or more.
Set Conditions
DBoost pressure is lower than the barometric pressure + 13 kPa for two
seconds.DBoost pressure sensor inoperative
DBoost pressure sensoropencircuit, short circuit,
or connector contact inoperative
DBoost pressure sensor hose disconnected
DEngine-ECU inoperative
Check the harness between the
engine-ECU and the boost pressure
sensor connector.
NG
Check the trouble symptoms.
Replace the engine-ECU.
Check the following connector:
D-113
NGOK
NG
Repair
RepairOK
NG
Replace the engine-ECU.
OKOK
OK
Check the following connector:
A-120NG
Check the trouble symptoms. NG
Repair
NG
NG
Check the vacuum hose between the
boost pressure sensor and the intake
manifold.
Replace the boost pressure sensor.
OK OK OK
Repair
NG
Repair
Check the trouble symptoms.
Check the harness between the
engine-ECU and the boost pressure
sensor connector, and repair if
necessary.
NG OK
NG
RepairCheck the following connector:
B-08NG
Measure at B-08 boost pressure
sensor connector
DConnect the connector.
(Test harness: MB991348 used)
DVoltage between 1 and the earth
(Engine: Idling)
OK:
1.2 - 1.6 V
DVoltage between 1 and the earth
OK:
When the accelerator pedal
is suddenly pressed from
the idling condition, the
voltage temporarily in-
creases from 1.2 V to 1.6
V.
Measure at D-113 engine-ECU
connector
DConnect the connector.
DVoltage between 85 and the
earth (Engine: Idling)
OK:
1.2 - 1.6 V
Check the harness between the
engine-ECU and the boost pressure
sensor connector.
Measure at B-08 boost pressure
sensor 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


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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-11
Code No. 15 Engine coolant temperature sensor systemProbable cause
Range of Check
DIgnition switch: ON, except for duringenginecranking
Set Conditions
DThe sensor output voltage for 3 seconds is 4.9V or higher (the coolant
temperature is approximately - 45_C or lower).
or
DThe sensor output voltage for 3 seconds is 0.2V or lower (the coolant
temperature is approximately 140_C or higher).DEngine coolant temperature sensor inoperative
DEngine coolant temperature sensoropencircuit,
short circuit, or connector contact inoperative
DEngine-ECU inoperative
OK
NGNG
Repair
OK
OKRepair
NGEngine coolant temperature sensor check
(Refer to P.13C-38.)
Replace the engine-ECU.NG
Replace the engine-ECU.OK NG
OK
Repair
Check the following connector:
B-36-3
NGCheck the trouble symptoms.NG
Measure at B-36-3 engine coolantsensor
connector
DDisconnect the connector and measure at
the harness side.
DVoltage between 1 and the earth
(Ignition switch: ON)
OK:
4.5 - 5.5 V
DContinuity between 2 and the earth
OK:
ContinuityCheck the following connectors:
B-36, D-112, D-113
Check the harness between the
engine-ECU and the engine coolant
temperature sensor connector.
Check the trouble symptoms. Replace
Code No. 16 Boost air temperature sensor (intake air
sensor) systemProbable cause
Range of Check
DIgnition switch:ON, except for duringenginecranking
Set Conditions
DThe sensor output voltage for 3 seconds is 4.6V or higher (the coolant
temperature is approximately 45_C or lower).
or
DThe sensor output voltage for 3 seconds is 0.3V or lower (the coolant
temperature is approximately 110_C or higher).DBoost air temperature sensor inoperative
DBoost air temperature sensoropencircuit, short
circuit, or connector contact inoperative
DEngine-ECU inoperative
OK
Measure at B-49 boost air temperature
connector
DDisconnect the connector and measure at
the harness side.
DVoltage between 1 and the earth
(Ignition switch: ON)
OK:
4.0 - 5.3 V
DContinuity between 2 and the earth
OK:
ContinuityNGCheck the following connectors:
D-112, D-113NG
Repair
OK
OKRepair
NGBoost air temperature sensor check
(Refer to P.13C-44.)
Check the trouble symptoms.
Replace the engine-ECU.NG
Replace the engine-ECU.OK NG
OK
Repair
Check the following connector:
B-49Replace
NGCheck the trouble symptoms.NG
Check the harness between the
engine-ECU and the boost air temperature
sensor connector.


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DIESEL FUEL <4M4> -Troubleshooting13C-12
Code No. 17 Vehicle speed sensor systemProbable cause
Range of Check
DIgnition switch: ON
DEngine speed: 2800 r/min or higher
DDriving with heavyload
Set Conditions
DSlower than vehicle speed of 3 km/hDVehicle speed sensor inoperative
DVehicle speed sensoropencircuit, short circuit, or
connector contact inoperative
DEngine-ECU inoperative
NG
YES
OK
Check the following connector:
D-113NG
Repair
OK
Check and repair the harness between the
engine-ECU and the vehicle speed sensor
connector
NOIs the speed meter working properly?
Check the trouble symptoms.
Replace the engine-ECU.
NG
OK
Repair
Check the following connectors:
C-09, D-113, E-113
NGCheck the trouble symptoms.NG
Vehicle speed sensor circuit check
Measure at D-113 engine-ECU connector
DConnect the connector.
DVoltage between 86 and the earth
(Ignition switch: ON)
OK:
When the vehicle is pushed to
move, the cycle change of 0.5 V is
repeated.


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DIESEL FUEL <4M4> -Troubleshooting13C-13
Code No. 18 Engine speed sensor (backup) systemProbable cause
Range of Check
DExcept for duringengine running andcranking
Set Conditions
DThe difference in the enginespeed sensor output for 4 seconds: 325 r/min or
moreDEngine speed sensor inoperative
DEngine speed sensoropencircuit, short circuit, or
connector contact inoperative
DEngine-ECU inoperative
Check the trouble symptoms.
OK
Check and repair the harness
between the enginespeed sensor
and the control relay connector.OK
OK
NG
Repair
(1) NGMeasure at B-36-2 enginespeed
sensor connector
DConnect the connector.
(Test harness: MB998348 used)
DVoltage between 2 and the earth
(Engine: cranking)
OK:
0.4 - 4.0 V
DVoltage between 2 and the earth
(Engine: Idling)
OK:
1.5 - 2.5 V
NG
Replace the enginespeed sensor.
Replace the engine-ECU.
Check the following connector:
B-36
NG
NG
Check the trouble symptoms.
OK
Repair NG
OK
Repair NG NG
OKRepair NG
NG
OKRepair NG
Check the following connector:
B-36-2
Check the trouble symptoms.
Measure at B-36-2 enginespeed
sensor connector
DDisconnect the connector and
measure at the harness side.
(1) Voltage between 3 and the earth
(Ignition switch: ON)
OK:
System voltage
(2) Voltage between 2 and the earth
(Ignition switch: ON)
OK:
4.8 - 5.2V
(3) Continuity between 1 and the
earth
OK:
Continuity(2) NG
(3) NG
Check the harness between the
engine-ECU and the enginespeed
sensor connector.
Replace the engine-ECU.
Check and repair the harness
between the enginespeed sensor
and the earth.
Check the following connector:
B-36
Check the trouble symptoms.
Check the following connectors:
B-36, D-112


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