2000 MITSUBISHI MONTERO ECU

GDI -General Information13A-4
SELF-DIAGNOSIS FUNCTION
DWhen an abnormality is detected in one
of the sensors or actuators related to
emission control, the engine warning lamp
(check engine lamp) illuminates or flashes
as a warning to the driver.
DWhen an abnormality is detected in one
of the sensors or actuators, a diagnosis
code corresponding to the abnormality is
output.
DThe engine-ECU records the engine
operating condition when the diagnosis
code is set. This data is called “freezeframe” data.
This data can be read by using the MUT-II,
and can then be used in simulation tests
for troubleshooting. M/T>
DThe RAM data inside the engine-ECU
or engine-A/T-ECU that is
related to the sensors and actuators can
be read by means of the MUT-II. In addition,
the actuators can be force-driven under
certain circumstances.
OTHER CONTROL FUNCTIONS
1. Fuel Pump Control
Turns the fuel pump relay ON so that current
is supplied to the fuel pump while the engine
is cranking or running.
2. A/C Relay Control
Turns the compressor clutch of the A/C
ON and OFF.3. Purge Control Solenoid Valve Control
Refer to GROUP 17.
4. EGR Control Servo Control
Refer to GROUP 17.
GENERAL SPECIFICATIONS
ItemsSpecifications
Throttle bodyThrottle bore mm65
Throttle position sensorVariable resistor type
Throttle valve control servoBrushless DC-motor type
Engine-ECUIdentification model No.E2T79271 Engine-ECU
Identification model No.E2T79271
E2T79272
Engine-Identification model No.E2T76277
A/T-ECU
E2T76278


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GDI -Troubleshooting 13A-10
Code No. Diagnosis item
P0206No.6 injector system
P0220LAccelerator pedal position sensor (1st channel) system
P0225LThrottle position sensor (2nd channel) system
P0300LIgnition coil (power transistor) system
P0301No.1 cylinder misfire detected.
P0302No.2 cylinder misfire detected.
P0303No.3 cylinder misfire detected.
P0304No.4 cylinder misfire detected.
P0305No.5 cylinder misfire detected.
P0306No.6 cylinder misfire detected.
P0335Crank angle sensor system
P0340Camshaft position sensor system
P0403EGR valve system
P0420Catalyst malfunction
P0443Purge control solenoid valve system
P1200Injector driver system
P1220LElectronic-controlled throttle valve system
P1221LThrottle valve position feedback system
P1222LThrottle control servo system
P1223LCommunication line system with throttle valve controller
P1225LAccelerator pedal position sensor (2nd channel) system
P1226LThrottle valve controller system
NOTE
1. If the engine warning lamp illuminates because of a malfunction of the engine-ECU, communication
between MUT-
IIand the engine-ECU is impossible. In this case, the diagnosis code cannot be read.
2. After the engine-ECU has detected a malfunction, the engine warning lamp illuminates when the
engine is next turned on and the same malfunction is re-detected. However, for items marked with
a“
L” in the diagnosis code number column, the engine warning lamp illuminates only on the first
detection of the malfunction.
If diagnosis code P0120, P0220, P0225 or P1225 is set, the engine warning lamp will flash. If the
1st and 2nd channels of the throttle postion sensor or the acccelerator pedal position sensor fail
at the same time, the engine warning lamp will also flash.
3. After the engine warning lamp illuminates, it will be switched off under the following conditions.
(1) When the engine-ECU monitored the power train malfunction three times* and met set condition
requirements, it detected no malfunction.
*: In this case, “one time” indicates from engine start to stop.
(2) For misfiring malfunction, when driving conditions (engine speed, engine coolant temperature,
etc.) are similar to those when the malfunction was first recorded.


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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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