2000 MITSUBISHI MONTERO Service Repair Manual

GDI -Troubleshooting 13A-27
Code No.P0125 Feedback systemProbable cause
Range of Check
DThe engine coolant temperature is approx. 80_C or more.
DDuring stoichiometric feedback control
DThe vechile is notbeing deccelerated.
Set Conditions
DOxygen sensor (front) output voltage hasbeen higher orlower than 0.5 V for
at least thirty seconds.DMalfunction of oxygen sensor (front)
DOpen or short circuit in the oxygen sensor (front)
circuit or loose connector contact
DMalfunction of engine-ECU
Repair
OK
Measure at oxygen sensor (front)
connector C-19.
DDisconnect the connector and
measure at the harness side.
DResistance between terminal 2
and earth
OK:
2Wor lessNGCheck the following connectors:
D-118, E-116NG
OK
Check the trouble symptoms.
Check the following connector:
C-19NG
Repair
(2) NGCheck the oxygen sensor (front).
(Refer to P.13A-230.)NGReplace
OK
Check the harness wire between
between the oxygen sensor (front)
and the engine-ECU.NG
Repair
NG
Replace the engine-ECU.
Repair
OK
Measure at oxygen sensor (front)
connector C-19.
DUse the test harness
(MD998464) to connect the
connector, and measure at the
pick-up harness side.
DEngine: 2,500r/min (after warming
up)
(1) Voltage between terminal 2 and
earth
OK:
0.5 V or less
(2) Voltage between terminal 4 and
earth
OK:
0 V and 0.8 V alternate.(1) NGCheck the following connectors:
D-118, E-116NG
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
NG
Repair
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
NG
Check the following connectors:
D-118, E-116NG
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
Check the following connector:
D-118
OKRepairNG
Check the trouble symptoms.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Replace the engine-ECU.
Repair
Check the following connectors:
D-118, E-116
Measure at engine-ECU connector
D-118.
DMeasure the voltage at the
engine-ECU terminal.
DEngine: 2,500r/min (after warming
up)
DVoltage between terminal 71 and
earth
OK:
0V and 0.8 V alternate.


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GDI -Troubleshooting 13A-28
Code No.P0130 Oxygen sensor (front) system
Probable cause
Range of Check
DThree minutes havebeenpassed since theengine has been started.
DThe engine coolant temperature is approx. 80_C or more.
DIntake air temperature is 20 - 50_C
DEngine speed is 1,200 r/min or more
DDriving on a level surface at constant speed.
Set Conditions
DThe oxygen sensor (front) output voltage is 4.5 V or more when the sensor
output voltage is 0.2 V or less and a voltage of 5 V isapplied to theoxygen
sensor (front) inside the engine-ECU.DMalfunction of oxygen sensor (front)
DOpen or short circuit in the oxygen sensor (front)
circuit or loose connector contact
DMalfunction of engine-ECU
Range of Check
DEngine speed is 3,000 r/min or less
DDuring driving
DDuring air/fuel ratio feedback control
Set Conditions
DThe oxygen sensor (front) output frequency is five or less per 12 seconds on
average.


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GDI -Troubleshooting 13A-29
Repair
OK
Measure at oxygen sensor (front)
connector C-19.
DDisconnect the connector and
measure at the harness side.
DResistance between terminal 2
and earth
OK:
2Wor lessNGCheck the following connectors:
D-118, E-116NG
OK
Check the trouble symptoms.
Check the following connector:
C-19NG
Repair
(2) NGCheck the oxygen sensor (front).
(Refer to P.13A-230.)NGReplace
OK
Check the harness wire between
between the oxygen sensor (front)
and the engine-ECU.NG
Repair
NG
Replace the engine-ECU.
Repair
OK
Measure at oxygen sensor (front)
connector C-19.
DUse the test harness
(MD998464) to connect the
connector, and measure at the
pick-up harness side.
DEngine: 2,500r/min (after warming
up)
(1) Voltage between terminal 2 and
earth
OK:
0.5 V or less
(2) Voltage between terminal 4 and
earth
OK:
0 V and 0.8 V alternate.(1) NGCheck the following connectors:
D-118, E-116NG
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
NG
Repair
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
NG
Check the following connectors:
D-118, E-116NG
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
OK
Check the following connector:
D-118
OKRepairNG
Check the trouble symptoms.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Replace the engine-ECU.
Repair
Check the following connectors:
D-118, E-116
Measure at engine-ECU connector
D-118.
DMeasure the voltage at the
engine-ECU terminal.
DEngine: 2,500r/min (after warming
up)
DVoltage between terminal 71 and
earth
OK:
0V and 0.8 V alternate.


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GDI -Troubleshooting 13A-30
Code No.P0135 Oxygen sensor heater (front) system
Probable cause
Range of Check
DThe engine coolant temperature is approx. 20_C or more.
DThe oxygen sensor heater (front) remains on.
DThe enginespeed is 50 r/min or more.
DBattery voltage is 11 - 16 V.
Set Conditions
DThe current, which flows through the oxygen sensor heater (front), is 0.2 A
or less or 3.5 A or more for six seconds.DMalfunction of oxygen sensor heater (front)
DOpen or short circuit in the oxygen sensor heater
(front) circuit or loose connector contact
DMalfunction of engine-ECU
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU, and repair if necessary.
Repair
OK
Measure at engine-ECU connector
D-118.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 89 and
earth
OK:
System voltageNGCheck the following connectors:
D-118, E-113NG
OK
Check the harness wires between
the oxygen sensor (front) and the
engine controlrelay, and repair if
necessary.
Measure at oxygen sensor (front)
connector C-19.
DDisconnect the connector and
measure at the harness side.
DResistance between terminals 1
and 3
OK:
4.5 - 8.0WNG
Replace
Repair
OK
Measure at oxygen sensor (front)
connector C-19.
DDisconnect the connector and
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal 1 and
earth
OK:
System voltageNGCheck the following connectors:
B-25X, D-128, E-113NG
OK
Check the following connector:
C-19NG
Repair
OK
Check the trouble symptoms.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.) NG
Replace the engine-ECU.
OK
Check the following connector:
D-118NG
Repair
OK
Check the harness wires between
the oxygen sensor (front) and the
engine-ECU and between the oxygen
sensor (front) and theengine control
relay.NG
Repair


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GDI -Troubleshooting 13A-31
Code No.P0136 Oxygen sensor (rear) system
Probable cause
Range of Check
DThree minutes havebeenpassed since theengine has been started.
DThe engine coolant temperature is approx. 80_C or more.
DIntake air temperature is 20 - 50_C
DEngine speed is 1,200 r/min or more
DDriving on a level surface at constant speed.
Set Conditions
DThe oxygen sensor (rear) output voltage is 4.5 V or more when the sensor
output voltage is 0.2 V or less and a voltage of 5 V isapplied to theoxygen
sensor (rear) inside the engine-ECU.DMalfunction of oxygen sensor (rear)
DOpen or short circuit in the oxygen sensor (rear)
circuit or loose connector contact
DMalfunction of engine-ECU
Range of Check
DTwo seconds have passed after the ECU detected anopencircuit.
DWhen the oxygen sensor (front) is ingood condition.
Set Conditions
DWhen the air/fuel ratio is rich, the oxygen sensor (front) output voltage is 0.5
V or more, the oxygen sensor (rear) output voltage is less than 0.1 V, and
the oxygen sensor (rear) output voltage fluctuates within 0.078 V.


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GDI -Troubleshooting 13A-32
Repair
OK
Measure at oxygen sensor (rear)
connector C-10.
DDisconnect the connector and
measure at the harness side.
DResistance between terminal 2
and earth
OK:
2Wor lessNGCheck the following connectors:
D-118, E-116NG
OK
Check the trouble symptoms.
Check the following connector:
C-10NG
Repair
(2) NGCheck the oxygen sensor (rear).
(Refer to P.13A-230.)NGReplace
OK
Check the harness wire between
between the oxygen sensor (rear)
and the engine-ECU.NG
Repair
NG
Replace the engine-ECU.
Repair
OK
Measure at oxygen sensor (rear)
connector C-10.
DUse the test harness
(MD998464) to connect the
connector, and measure at the
pick-up harness side.
DEngine: 2,500r/min (after warming
up)
(1) Voltage between terminal 2 and
earth
OK:
0.5 V or less
(2) Voltage between terminal (4) and
earth
OK:
0 V and 0.8 V alternate.(1) NGCheck the following connectors:
D-118, E-116NG
OK
Check the harness wire between the
oxygen sensor (rear) and the
engine-ECU, and repair if necessary.
OK
NG
Repair
OK
Check the harness wire between the
oxygen sensor (rear) and the
engine-ECU, and repair if necessary.
OK
NG
Check the following connectors:
D-117, E-116NG
OK
Check the harness wire between the
oxygen sensor (rear) and the
engine-ECU, and repair if necessary.
OK
Check the following connector:
D-117
OKRepairNG
Check the trouble symptoms.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Replace the engine-ECU.
Repair
Check the following connectors:
D-117, E-116
Measure at engine-ECU connector
D-117.
DMeasure the voltage at the
engine-ECU terminal.
DEngine: 2,500r/min (after warming
up)
DVoltage between terminal 53 and
earth
OK:
0V and 0.8 V alternate.


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GDI -Troubleshooting 13A-33
Code No.P0141 Oxygen sensor heater (rear) system
Probable cause
Range of Check
DThe engine coolant temperature is approx. 20_C or more.
DThe oxygen sensor heater (rear) remains on.
DThe enginespeed is 50 r/min or more.
DBattery voltage is 11 - 16 V.
Set Conditions
DThe current, which flows through the oxygen sensor heater (rear), is 0.2 A or
less or 3.5 A or more for six seconds.DMalfunction of oxygen sensor heater (rear)
DOpen or short circuit in the oxygen sensor heater
(rear) circuit or loose connector contact
DMalfunction of engine-ECU
OK
Check the harness wire between the
oxygen sensor (rear) and the
engine-ECU, and repair if necessary.
Repair
OK
Measure at engine-ECU connector
D-118.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 90 and
earth
OK:
System voltageNGCheck the following connectors:
D-118, E-113NG
OK
Check the harness wires between
the oxygen sensor (rear) and the
engine controlrelay, and repair if
necessary.
Measure at oxygen sensor (rear)
connector C-10.
DDisconnect the connector and
measure at the harness side.
DResistance between terminals 1
and 3
OK:
4.5 - 8.0WNG
Replace
Repair
OK
Measure at oxygen sensor (rear)
connector C-10.
DDisconnect the connector and
measure at the harness side.
DIgnition switch: ON
DVoltage between terminal 1 and
earth
OK:
System voltageNGCheck the following connectors:
B-25X, D-128, E-113NG
OK
Check the following connector:
C-10NG
Repair
OK
Check the trouble symptoms.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.) NG
Replace the engine-ECU.
OK
Check the following connector:
D-118NG
Repair
OK
Check the harness wires between
the oxygen sensor (rear) and the
engine-ECU and between the oxygen
sensor (rear) and theengine control
relay.NG
Repair


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GDI -Troubleshooting 13A-34
Code No.P0170 Abnormal fuel systemProbable cause
Range of Check
DEngine: Being learning the air - fuel ratio
Set Conditions
DTen seconds or more havebeenpassed while the fuel injection amount
compensation value is too low.
or
DTen seconds or more havebeenpassed while the fuel injection amount
compensation value is too high.DMalfunction of fuel supply system
DMalfunction of oxygen sensor (front)
DMalfunction of intake air temperature sensor
DMalfunction of barometric pressure sensor
DMalfunction of air flow sensor
DMalfunction of engine-ECU
Repair
OK
MUT-
IIData list
74 Fuel pressure sensor (Refer to
13A-105, DATA LIST
REFERENCE TABLE.)NGCheck fuel leakage around the fuel
pump (high-pressure) line.NG
NO
Check the air intake from the intake
hose and intake manifold.NG
Repair
OK
Check the oxygen sensor (front)
(Refer to P.13A-230.)NG
Replace
MUT-
IISelf-Diag Code
Is any diagnosis code other than
No.P0170 output?YESRefer to P.13A-15, INSPECTION
CHART FOR DIAGNOSIS CODES.
OK
Check the exhaust gas leaks from
the exhaust manifold.NG
Repair
OK
Check the throttle body (around the
throttle valve), and clean if
necessary. (Refer to P.13A-220).NG
Cleaning
OK
MUT-
IIData list
11 Oxygen sensor (front)
12 Air flow sensor
13 Intake air temperature sensor
21 Engine coolant temperature
sensor
25 Barometric pressure sensor
(Refer to 13A-105, DATA LIST
REFERENCE TABLE.)
Reference
If all the service data is normal, go
to “OK.”
If any abnormal service is found, go
to “NG.”NGRefer to the Inspection procedure for
the sensor, which is indicated by the
abnormal service data.
(Refer to P.13A-15, INSPECTION
CHART FOR DIAGNOSIS CODES.)OK
Replace the fuel pump
(high-pressure).
Check the purge control solenoid
valve (Refer to GROUP 17 -
Emission Control).NG
Replace
OK
To the nextpageOK


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