2000 MITSUBISHI MONTERO ECU

GDI -Troubleshooting 13A-114
Terminal
No.Normal condition Check requirements (engine condition) Check item
63Stop lamp switchDepress the brake pedal.System voltage
Release the brake pedal.0-3V
65A/C switch (2nd channel)Refer to GROUP 55 - Troubleshooting “Check at the A/C-ECU
terminal, engine-ECU output terminals.”
66Clutch switchDepress the clutch pedal.0-3V
Release the clutch pedal.System voltage
68Ignition switch-STEngine: Cranking8V or more
71Oxygen sensor (front)Engine: Warm up, and then hold the
engine speed at 2,500r/min (Use a
digital voltmeter).0«0.8 V alternates.
76Air flow sensor reset signalEngine: Idling0-1V
Engine: 3,000 r/min6-9V
78Throttle position sensor
(2nd channel)Ignition switch:
ONRelease the
accelerator pedal.4.5 - 5.5 V
Depress the
accelerator pedal
fully.0.4 - 0.6 V
79Accelerator pedal position
switchIgnition switch:
ONRelease the
accelerator pedal.0-1V
Depress the
accelerator pedal
fully.4V or more
80Vehicle speed sensorDIgnition switch: ON
DMove the vehicle forward.0«system voltage
alternates.
83A/C switch (1st channel)Engine: IdlingA/C switch: OFF0-3V
A/C switch: ON
(Compressor is
operating)System voltage
88Small lamp switchLighting switch: OFF0-3V
Lighting switch: ON (Taillamp: ON)System voltage
89Oxygen sensor heaterEngine: Idling0-3V
(front)
Engine: 3,500 r/minSystem voltage
90Oxygen sensor heaterEngine: Idling0-3V
(rear)
Engine: 3,500 r/minSystem voltage
92Fuel pressure sensorEngine: Idling0.3 - 4.7 V


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GDI -Troubleshooting 13A-115
Terminal
No.Normal condition Check requirements (engine condition) Check item
94Accelerator pedal position
sensor (1st channel)Ignition switch:
ONRelease the acceler-
ator pedal.0.3 - 1.0 V*1
Depress the
accelerator pedal
fully.4.2 - 5.5 V*2
96Injector open circuit check
signalEngine: Increase engine speed from
idle speed to 4,000 r/min.Decreases slightly (approx.
0.7V) from 4.5 V - 5.0 V.
99Ignition switch - IGIgnition switch: ONSystem voltage
NOTE
Check if the difference in output between *1 and *2 is 4 V or more.
CHECK CHART FOR RESISTANCE AND CONTINUITY
BETWEEN TERMINALS
1. Turn the ignition switch to OFF.
2. Disconnect the engine-ECU connector.
3. Measure the resistance and check for continuity between
the terminals of the engine-ECU harness-side connector
while referring to the check chart.
NOTE
(1) When measuring resistance and checking continuity,
a harness for checking contact pin pressure should
be used instead of inserting a test probe.
(2) Checking need not be carried out in the order given
in the chart.
Caution
If the terminals that should be checked are mistaken,
or if connector terminals are not correctly shorted
to earth, damage may be caused to the vehicle wiring,
sensors, engine-ECU and/or ohmmeter.
Be careful to prevent this!
4. If the ohmmeter shows any deviation from the standard
value, check the corresponding sensor, actuator and
related electrical wiring, and then repair or replace.
5. After repair or replacement, recheck with the ohmmeter
to confirm that the repair or replacement has corrected
the problem.


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GDI -Troubleshooting 13A-127
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-A/T-ECU to
DIAGNOSIS 2 mode using the MUT-II, and then carry
out a road test.
2. Take a reading of the diagnosis code and repair the
problem location.
3. Turn the ignition switch to the LOCK (OFF) position, and
then back to ON again.
NOTE
By turning the ignition switch to the LOCK (OFF) position,
the engine-A/T-ECU will switch the DIAGNOSIS 2 mode
to DIAGNOSIS 1 mode.
4. Erase the diagnosis codes.
INSPECTION USING MUT-II
DATA LIST AND
ACTUATOR TESTING
1. Carry out inspection by means of the data list and 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-129
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-A/T-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-A/T-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-131
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No.11 Oxygen sensor systemProbable 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 - 30_C
DEngine speed is 1,200 r/min or more
DDriving on a level surface at constant speed.
Set Conditions
DThe oxygen sensor 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 inside the engine-A/T-ECU.DMalfunction of oxygen sensor
DOpen or short circuit in the oxygen sensor circuit
or loose connector contact
DMalfunction of engine-A/T-ECU


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GDI -Troubleshooting 13A-132
Repair
OK
Measure at oxygen sensor (front)
connector C-20.
DDisconnect the connector and
measure at the harness side.
DResistance between terminal 2
and earth
OK:
2Wor lessNGCheck the following connectors:
D-121, E-116NG
OK
Check the trouble symptoms.
Check the following connector:
C-20NG
Repair
(2) NGCheck the oxygen sensor. (Refer to
P.13A-230.)NGReplace
OK
Check the harness wire between
between the oxygen sensor and the
engine-A/T-ECU.NG
Repair
NG
Replace the engine-A/T-ECU.
Repair
OK
Measure at oxygen sensor connector
C-20.
DUse the test harness
(MD998464) to connect the
connector, and measure at the
pick-up harness side.
DEngine: 2,500r/min (after warming
up)
DSelector lever position: P
(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-121, E-116NG
OK
Check the harness wire between the
oxygen sensor and the
engine-A/T-ECU, and repair if
necessary.
OK
NG
Repair
OK
Check the harness wire between the
oxygen sensor and the
engine-A/T-ECU, and repair if
necessary.
OK
NG
Check the following connectors:
D-121, E-116NG
OK
Check the harness wire between the
oxygen sensor and the
engine-A/T-ECU, and repair if
necessary.
OK
Check the following connectors:
D-121, E-116
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-121, E-116
Measure at engine-A/T-ECU
connector D-121.
DMeasure the voltage at the
engine-A/T-ECU terminal.
DEngine: 2,500r/min (after warming
up)
DSelector lever position: P
DVoltage between terminal 72 and
earth
OK:
0V and 0.8 V alternate.


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GDI -Troubleshooting 13A-133
Code No.12 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-A/T-ECU
(3) NGCheck the following connector:
D-121NG
Repair
(2) NGCheck the following connector:
B-25XNG
Repair
OK
Check the harness between the air
flow sensor and the engine-A/T-ECU,
and repair if necessary.
MUT-
IIData list
12 Air flow sensor (Refer to
13A-198, 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-A/T-ECU
connector D-120.
DMeasure the voltage at the
engine-A/T-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 65 and
earth
OK:
4.8 - 5.2 VOKCheck the following connector:
D-120
NG
Repair
OK
Replace the air flow sensor.
NG
Check the following connector:
D-120NG
Repair
OK
Check the harness between the air
flow sensor and the engine-A/T-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-A/T-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-A/T-ECU.NG
Repair
OK
Check the trouble symptoms.NGReplace the engine-A/T-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-119NG
Repair
OK
Check the harness between the air
flow sensor and the engine-A/T-ECU.NG
Repair
OK
To the nextpage


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GDI -Troubleshooting 13A-134
OK
Check the harness between the air
flow sensor and the engine-A/T-ECU.NG
Repair
OK
Check the harnesses between the
air flow sensor and the
engine-A/T-ECU and between the air
flow sensor and theengine control
relay, 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: 3,000 r/min
6-9VNGCheck the following connector:
D-119NGRepair
OK
Check the trouble symptoms.
NG
Replace the engine-A/T-ECU.
Check the trouble symptoms.
NG
Check the following connectors:
D-120, D-121, B-25XNG
Repair
OK
Measure the output waveform from
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
DSelector lever position: P
DVoltage between terminal 3 and
earth
OK:
Waveform should be dis-
played on P.13A - 211 (In-
spection Procedure Using
an Analyzer) and noise
should not be displayed in
the waveformNGReplace the air flow sensor.
OK
Check the trouble symptoms.
NG
Replace the engine-A/T-ECU.OK


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