ECU MITSUBISHI MONTERO 2000 Service User Guide

GDI -Troubleshooting 13A-11
4. Sensor 1 indicates the sensor mounted at a position closest to the engine, and sensor 2 indicates
the sensor mounted at the position second closest to the engine.
METHOD OF READING AND ERASING DIAGNOSIS
CODES
Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points.
DIAGNOSIS USING DIAGNOSIS 2 MODE
1. Switch the diagnosis mode of the engine control unit
to DIAGNOSIS 2 mode using the MUT-II.
2. Carry out a road test.
3. Take a reading of the diagnosis code and repair the
problem location.
4. Turn the ignition switch to OFF and then back to ON
again.
NOTE
By turning the ignition switch to OFF, the ENGINE-ECU will
switch the diagnosis mode from DIAGNOSIS 2 mode to
DIAGNOSIS 1 mode.
5. Erase the diagnosis codes.
INSPECTION USING MUT-II
DATA LIST AND
ACTUATOR TESTING
1. Carry out inspection by means of the data list and the
actuator test function. If there is an abnormality, check
and repair the chassis harnesses and components.
2. After repairing, re-check using the MUT-IIand check that
the abnormal input and output have returned to normal
as a result of the repairs.
3. Erase the diagnosis code memory.
4. Remove the MUT-II, and then start the engine again and
carry out a road test to confirm that the problem has
disappeared.


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GDI -Troubleshooting 13A-12
FREEZE FRAME DATA
When the engine-ECU detects a malfunction and stores a
diagnosis code, it also stores a current status of the engine.
This function is called “Freeze frame data.” By analyzing
this “freeze frame” data with the MUT-II, an effective
troubleshooting can be performed.
Data itemUnit
Engine coolant temperature sensor_C
Engine speedr/min
Vehicle speedkm/h
Long-term fuel compensation (long-term
fuel trim)%
Short-term fuel compensation (short-term
fuel trim)%
Fuel control condi-Open loopOL
tion
Closed loopCL
Open loop owing to
drive conditionOL-DRV.
Open loop owing to
system malfunctionOL-SYS.
Closed loop based
on one oxygen sen-
sorCL-H02S
Calculation load value%
Diagnosis code during data recording-
NOTE
If malfunctions have been detected in multiple systems, store
one malfunction only, which has been detected first.
READINESS TEST STATUS
The engine-ECU monitors the following main diagnosis items,
judges if these items are in good condition or not, and the
stores its history. This history can be read out by using MUT-II.
(If the ECU has judged a item before, the MUT-II displays
“Complete.”)
In addition, if diagnosis codes are erased or the battery
cable is disconnected, this history will also be erased (the
memory will be reset).
DCatalyst: P0420
DOxygen sensor: P0130
DOxygen sensor heater: P0135, P0141


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GDI -Troubleshooting 13A-14
Malfunctioning item Control contents during malfunction
Accelerator pedal position sen-
sor (1st channel)1. Suspends lean burn operation.
2. Controls the throttle valve position by using signals from the accelerator pedal
position sensor (2nd channel). (However, this control is not applicable if the
voltage difference between the accelerator pedal position sensor (1st channel)
and accelerator pedal position sensor (2nd channel) is 1.0 V or higher.)
3. Also suspends the electronic-controlled throttle valve system when the
accelerator pedal position sensor (2nd channel) is defective.
Throttle position sensor (1st
channel)1. Suspends lean burn operation.
2.Controls throttle opening angle feedback by using signals from throttle position
sensor (2nd channel). (However, the controlling system is not applied when
the throttle position sensor (1st channel) and throttle position sensor (2nd
channel) combination output voltage is outside 4 - 6 V.)
3.Refrains from controlling the throttle opening angle feedback when throttle
position sensor (2nd channel) is also defective.
Electronic-controlled throttle
valve system1. Suspends the electronic controlled throttle valve system.
2. Suspends lean burn operation.
3. Suspends the idle speed feedback control.
Throttle valve position feed-
back1. Suspends the electronic controlled throttle valve system.
2. Suspends lean burn operation.
3. Suspends the engine speed feedback control.
However, if the throttle valve opening angle is significantly wide, this system carries
out the following controls.
1. Always cuts the fuel supply to three cylinders.
2. Cuts the fuel supply when the engine speed reaches 3,000 r/min or more.
Throttle control servo1. Suspends the electronic-controlled throttle valve system.
2. Suspends lean burn operation.
3. Suspends the engine speed feedback control.
Communication line between
the throttle valve controller and
the ECU1. Communication error between the throttle valve controller and the engine-ECU:
DSuspends lean burn operation.
DCuts the fuel supply when the engine speed reaches 3,000 r/min or
more.
DSuspends the cruise-control.
2. Communication error between the throttle valve controller and the engine-ECU:
DSuspends lean burn operation.
DCuts the fuel supply when the engine speed reaches 3,000 r/min or
more.
DSuspends the cruise-control.
DThe throttle valve controller controls the throttle valve opening angle by
using signals from accelerator pedal position sensor (2nd channel).
Throttle valve controller1. Suspends the electronic-controlled throttle valve system.
2. Suspends lean burn operation.
3. Suspends the engine speed feedback control.
NOTE
If the electronic-controlled throttle valve system is suspended, the engine warning lamp will illuminate.


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GDI -Troubleshooting 13A-16
Code No.Reference page Diagnosis item
P0443Purge control solenoid valve system13A-62
P0500Vehicle speed sensor system13A-63
P1200Injector driver system13A-63
P1220LElectronic-controlled throttle valve system13A-64
P1221LThrottle valve position feedback system13A-65
P1222LThrottle control servo system13A-66
P1223LCommunication line with throttle valve controller13A-67
P1225LAccelerator pedal position sensor (2nd channel) system13A-68
P1226LThrottle valve controller system13A-69
P1500Alternator FR terminal system13A-70
P1610Immobilizer system13A-71
NOTE
1. Do not replace the engine-ECU until a through terminal check reveals there are no short/open circuit.
2. Check that the engine-ECU earth circuit is normal before checking for the cause of the problem.
3. After the engine-ECU has detected a malfunction, a diagnosis code is recorded the next time the
engine is started and the same malfunction is re-detected. However, for items marked with a “
L”,
the diagnosis code is recorded on the first detection of the malfunction.
4. Sensor 1 indicates the sensor mounted at a position closest to the engine, and sensor 2 indicates
the sensor mounted at the position second closest to the engine.


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GDI -Troubleshooting 13A-17
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No.P0100 Air flow sensor systemProbable cause
Range of Check
DEngine speed: 500 r/min or more
Set Conditions
DThe sensor output frequency is 3.3 Hz or less for four seconds.DMalfunction of air flow sensor
DOpen or short circuit in air flow sensor circuit or
loose connector contact
DMalfunction of engine-ECU
(3) NGCheck the following connector:
D-118NG
Repair
(2) NGCheck the following connector:
B-25XNG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
MUT-
IIData list
12 Air flow sensor (Refer to
P.13A-105, DATA LIST
REFERENCE TABLE.)OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Check the following connector:
B-120NG
Repair
OK
Measure at air flow sensor connector
B-120.
DDisconnect the connector and
measure at the harness side.
(1) Voltage between terminal 3 and
earth (Ignition switch: ON)
OK:
4.8 - 5.2 V
(2) Voltage between terminal 4 and
earth (Ignition switch: ON)
OK:
System voltage
(3) Resistance between terminal 5
and earth
OK:
2Wor less(1) NGMeasure at engine-ECU connector
D-117.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 61 and
earth
OK:
4.8 - 5.2 VOKCheck the following connector:
D-117
NG
Repair
OK
Replace the air flow sensor.
NG
Check the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
Check the harness between the air
flow sensor and theengine control
relay, and repair if necessary.
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
Measure at air flow sensor connector
B-120.
DUse test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
DIgnition switch: ON
DVoltage between terminal 7 and
earth
OK:
7-8VNGCheck the following connector:
D-118NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
To the nextpage


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GDI -Troubleshooting 13A-18
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the harnesses between the
air flow sensor and the engine-ECU
and between the air flow sensor and
the engine controlrelay, and repair if
necessary.
From the previouspage
OK
Measure at air flow sensor connector
B-120.
DUse test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
DSelector lever position: P
DVoltage between terminal 7 and
earth
OK:
Engine: Idling
0-1V
Engine speed: 3000 r/min
6-9VNGCheck the following connector:
D-118NGRepair
OK
Check the trouble symptoms.
NG
Replace the engine-ECU.
Check the trouble symptoms.
NG
Check the following connectors:
B-25X, D-117, D-118NG
Repair
OK
Measure the output wave form at air
flow sensor connector B-120 (by
using an analyzer).
DUse test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
DEngine: Idling
DVoltage between terminal 3 and
earth
OK:
Waveforms should be dis-
played on P.13A-118 (In-
spection Procedure Using
an Analyzer) and noise
should not be displayed in
the waveform.NGReplace the air flow sensor.
OK
Check the trouble symptoms.
NG
Replace the engine-ECU.OK


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GDI -Troubleshooting 13A-19
Code No.P0105 Barometric pressure sensor systemProbable cause
Range of Check
DTwo seconds have passed since the ignition switch is turned ON or the
engine startingprocess is completed.
DBattery voltage: 8 V or more
Set Conditions
DThe sensor output voltage is 4.5 V or more for four seconds (equivalent to
114 kPa of barometric pressure)
or
DThe sensor output voltage is 0.2 V or less (equivalent to 53 kPa of
barometric pressure)DMalfunction of barometric pressure sensor
DOpen or short circuit in barometric pressure
sensor circuit or loose connector contact
DMalfunction of engine-ECU
(2) NGCheck the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
MUT-
IIData list
25 Barometric pressure sensor
(Refer to P.13A-105, DATA LIST
REFERENCE TABLE.)OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
NG
Repair
OK
Measure at air flow sensor connector
B-120.
DDisconnect the connector and
measure at the harness side.
(1) Voltage between terminal 1 and
earth (Ignition switch: ON)
OK:
4.8 - 5.2 V
(2) Resistance between terminal 5
and earth
OK:
2Wor less(1) NGMeasure at engine-ECU connector
D-117.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 41 and
earth
OK:
4.8 - 5.2 VOKCheck the following connector:
D-117
NG
Repair
NG
Check the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
Measure at air flow sensor connector
B-120.
DConnect connector terminals
No.1, No.2 and No.5 only by
using test harness (MB991709),
and measure at the pick-up
harness.
DIgnition switch: ON
(1) Voltage between terminal 1 and
earth
OK:
4.8 - 5.2 V
(2) Voltage between terminal 2 and
earth
OK:
Altitude 0 m: 3.7 - 4.3 V
Altitude 1200 m:
3.2 - 3.8 V
(3) Voltage between terminal 5 and
earth
OK:
0.5 V or less(1) NGCheck the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
OK
To the nextpage(3) NG
(2) NG
Replace the air flow sensor.
NG
Check the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
Check the following connector:
B-120
Check the trouble symptoms.


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GDI -Troubleshooting 13A-20
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
From the previouspage
OK
Measure at engine-ECU connector
D-117.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 51 and
earth
OK:
Altitude 0 m: 3.7 - 4.3 V
Altitude 1200 m:
3.2 - 3.8 VNGCheck the following connector:
D-117NGRepair
OK
Check the trouble symptoms.
OKCheck the following connector:
D-117NG
Repair
NG
Replace the engine-ECU.


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GDI -Troubleshooting 13A-21
Code No.P0110 Intake air temperature sensor systemProbable cause
Range of Check
DTwo seconds have passed since the ignition switch is turned ON or the
engine startingprocess is completed.
Set Conditions
DThe sensor output voltage is 4.6 V or more for four seconds (equivalent to
-45_C of intake air temperature)
or
DThe sensor output voltage is 0.2 V or more for four seconds (equivalent to
125_C of intake air temperature)DMalfunction of intake air temperature sensor
DOpen or short circuit in intake air temperature
sensor or loose connector contact
DMalfunction of engine-ECU
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
MUT-
IIData list
13 Intake air temperature sensor
OK:
Roughly the same as ambi-
ent temperature.OKTransient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Check the intake air temperature
sensor itself.
(Refer to P.13A-1227.)NG
Repair
OK
Measure at air flow sensor connector
B-120.
DDisconnect the connector and
measure at the harness side.
(1) Resistance between terminal 5
and earth
OK:
2Wor less
(2) Voltage between terminal 6 and
earth
(Ignition switch: ON)
OK:
4.8 - 5.2 V(1) NG
NGRepair
NG
Repair
NG
Check the following connector:
D-117NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
Check following connector:
B-120NG
Repair
(2) NGMeasure at engine-ECU connector
D-117.
DMeasure the voltage at the
engine-ECU terminal.
DDisconnect connector B-120.
DIgnition switch: ON
DVoltage between terminal 62 and
earth
OK:
4.8 - 5.2 VOKCheck the following connector:
D-117
OK
Check the harness between the air
flow sensor and the engine-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-ECU.
OK
To the nextpage
Check the following connector:
D-118


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GDI -Troubleshooting 13A-22
OK
Measure at air flow sensor connector
B-120.
DUse the test harness (MB991709)
to connect only terminals 5 and
6, and then measure at the
pickup harness.
DIgnition switch: ON
DVoltage between terminal 6 and
earth
OK:
Ambient temperature 0_C:
3.2 - 3.8 V
Ambient temperature 20_C:
2.3 - 2.9 V
Ambient temperature 40_C:
1.5 - 2.1 V
Ambient temperature 80_C:
0.4 - 1.0 VNGCheck the following connectors:
D-117, D-118NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU,
and repair if necessary.
OK
Check the trouble symptoms.NGReplace the engine-ECU.
From the previouspage
Code No.P0115 Engine coolant temperature sensor
systemProbable cause
Range of Check
DEngine: Two seconds after theengine has beenstarted
Set Conditions
DThe sensor output voltage is 4.6 V or more for four seconds (equivalent to
-45_C of engine coolant temperature)
or
DThe sensor output voltage is 0.1 V or less for four seconds (equivalent to
140_C of engine coolant temperature)DMalfunction of engine coolant temperaturesensor
DOpen or short circuit in theengine coolant
temperature sensor circuit or loose connector
contact
DMalfunction of engine-ECU
Range of Check
DEngine: After starting
Set Conditions
DThe engine coolant temperature has reduced fromover 40_C to less than
40_C, and that condition has lasted for five minutes or more.


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