MITSUBISHI MONTERO 2000 Service Repair Manual

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-128
FAIL-SAFE FUNCTION REFERENCE TABLE
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor1. Suspends lean burn operation.
2. Uses the throttle position sensor signal and engine speed signal (crank angle
sensor signal) to take reading of the basic injector drive time and basic ignition
timing from the pre - set mapping.
Intake air temperature sensorControls as if the intake air temperature is 25_
C.
Throttle position sensor (2nd
channel)1. Suspends lean burn operation.
2. Controls the throttle opening angle feedback (half as much as the opening
rate in the normal condition) by using signals from the throttle position sensor
(1st channel). However, this controlling system is not applied if 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 if the throttle
position sensor (1st channel) is also defective.
Engine coolant temperature
sensorControls as if the engine coolant temperature is 80_
C. (Moreover, the control system
is working until the ignition switch is turned OFF if the sensor signal returns to normal.)
Camshaft position sensorCuts the fuel supply once a malfunction is detected. (Only when there has been
no occasion of detecting No.1 cylinder top dead centre after the ignition switch
is turned ON.)
Vehicle speed sensor1. Suspends lean burn operation. However, the control is cancelled as a certain
time passes by with the engine speed of 1,500 r/min or more.
2. Suspends lean burn operation during the engine idling.
Barometric pressure sensorControls as if the barometric pressure is 101 kPa.
Detonation sensorFixes the ignition timing as that for regular gasoline.
Injector1. Suspends lean burn operation.
2. Suspends the exhaust gas recirculation.
Ignition coil (incorporating pow-
er transistor)1. Suspends lean burn operation.
2. Cuts off the fuel supply to cylinders with an abnormal ignition signal.
Fuel pressure sensor1. Controls as if the fuel pressure is 5MPa.
2. Suspends fuel injection. (when the low pressure is detected and the engine
speed is more than 3,000r/min)
Alternator FR terminalRefrains from controlling to suppress the alternator output to electrical load.
(Operated as a normal alternator)
Accelerator pedal position sen-
sor (2nd channel)1. Suspends lean burn operation.
2. Controls the throttle valve position by using signals from the accelerator pedal
position sensor (1st channel). (However, the control system is not applicable
if the difference from the accelerator pedal position sensor (1st channel) output
voltage is 1.0V or higher.)
3
. Suspends the electronic controlled throttle valve system if accelerator pedal
position sensor (1st channel) is also defective.


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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-130
INSPECTION CHART FOR DIAGNOSIS CODES
Code No.Diagnosis itemReference page
11Oxygen sensor system13A-131
12Air flow sensor system13A-133
13Intake air temperature sensor system13A-135
14Throttle position sensor (2nd channel) system13A-137
21Engine coolant temperature sensor system13A-138
22Crank angle sensor system13A-140
23Camshaft position sensor system13A-142
24Vehicle speed sensor system13A-144
25Barometric pressure sensor system13A-145
31Detonation sensor system13A-146
41Injector system13A-147
44Ignition coil (incorporating power transistor) system (for No. 1 and No. 4 cylinders)13A-148
52Ignition coil (incorporating power transistor) system (for No. 2 and No. 5 cylinders)13A-148
53Ignition coil (incorporating power transistor) system (for No. 3 and No. 6 cylinders)13A-148
54Immobilizer system13A-150
56Abnormal fuel pressure system13A-151
64Alternator FR terminal system13A-153
77Accelerator pedal position sensor (2nd channel) system13A-154
78Accelerator pedal position sensor (1st channel) system13A-156
79Throttle position sensor (1st channel) system13A-158
89Abnormality in fuel pressure system13A-160
91Electronic-controlled throttle valve system13A-161
92Throttle valve position feedback system13A-162
93Throttle valve control servo system13A-163
94Communication line system with throttle valve controller13A-164
96Throttle valve controller system13A-165
NOTE
Code No. 56 may be also output when air is sucked in high-pressure fuel line due to no fuel supply.


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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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GDI -Troubleshooting13A-135
Code No.13 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-A/T-ECU
OK
Check the harness between the air
flow sensor and the engine-A/T-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-227.)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-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 following connector:
B-67NG
Repair
(2) NGMeasure at engine-A/T-ECU
connector D-120.
DMeasure the voltage at the
engine-A/T-ECU terminal.
DDisconnect connector B-120.
DIgnition switch: ON
DVoltage between terminal 64 and
earth
OK:
4.8 - 5.2 VOKCheck the following connector:
D-120
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
To the nextpage
Check the following connector:
D-121


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GDI -Troubleshooting 13A-136
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-120, D-121NG
Repair
OK
Check the harness between the air
flow sensor and the engine-A/T-ECU,
and repair if necessary.
OK
Check the trouble symptoms.NGReplace the engine-A/T-ECU.
From the previouspage


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