Mitsubishi FUEL User manual

13A-1
FUEL
CONTENTS
MULTIPOINT FUEL INJECTION (MPI) 13A....................................
GASOLINE DIRECT INJECTION (GDI) 13I...................................

13A-2
MULTIPOINT FUEL
INJECTION (MPI)
CONTENTS
MULTIPOINT FUEL INJECTION (MPI)
<4G6> 3..............................
GENERAL 3...............................
Outline of Changes 3........................
GENERAL INFORMATION 3................
Self-diagnosis Function 3.....................
General Specifications 3.....................
SERVICE SPECIFICATIONS 3..............
TROUBLESHOOTING 4....................
Diagnosis Function 4........................
Fail-safe Function Reference Table 7..........
Inspection Chart for Diagnosis Codes 8.......
Inspection Procedure Classified by Diagnosis
Code 10....................................
Inspection Chart for Trouble Symptoms 45.....
Inspection Procedure for Trouble Symptoms
46.........................................
Data List Reference Table 75.................
Actuator Test Reference Table 80.............
Check at the Engine-ECU Terminals 81.......
Inspection Procedure Using an Analyzer 88....
ON-VEHICLE SERVICE 89.................
Oxygen Sensor Check 89....................
MULTIPOINT FUEL INJECTION (MPI)
<6A1> 91.............................
GENERAL 91..............................
Outline of Changes 91.......................
GENERAL INFORMATION 91...............
Self-diagnosis Function 91....................
General Specifications 91....................
Multipoint Fuel Injection System Diagram 92...
SERVICE SPECIFICATIONS 93.............
TROUBLESHOOTING 94...................
Diagnosis Function 94.......................
Fail-safe Function Reference Table 98.........
Inspection Chart for Diagnosis Codes 99......
Inspection Procedure Classified by Diagnosis
Code 101...................................
Inspection Chart for Trouble Symptoms 145....
Inspection Procedure for Trouble Symptoms
146........................................
Data List Reference Table 176................
Actuator Test Reference Table 183............
Check at the Engine-ECU Terminals 185......
Inspection Procedure Using an Analyzer 192...
ON-VEHICLE SERVICE 193...............
Oxygen Sensor Check 193...................

MPI <4G6> - General/General Information/Service Specifications 13A-3
MULTIPOINT FUEL INJECTION (MPI) <4G6>
GENERAL
OUTLINE OF CHANGES
Due to the changes shown below, the service procedures regarding the different description from the
previous version have been established.
DOn-board Diagnostics System has been adopted to expand the diagnostic items and to change diagnosis
code numbering system.
DThe engine-ECU has been changed. <Vehicles with M/T>
DAn engine-A/T-ECU has been adopted. <Vehicles with A/T>
DAn ignition failure sensor has been adopted.
DThe injector has been changed.
DThe oxygen sensor has been changed.
GENERAL INFORMATION
SELF-DIAGNOSIS FUNCTION
Following functions have been added.
DThe engine-ECU records the engine operating condition when the diagnosis code is set. This data
is called “freeze frame” data. It can be read by using the MUT-II, and can be used in simulation
tests for troubleshooting.
GENERAL SPECIFICATIONS
Items Specifications
Engine-ECU <M/T> Identification model No. E2T67693
Engine-A/T-ECU <A/T> Identification model No. E6T30571
Actuators Injector identification mark CDH240
SERVICE SPECIFICATIONS
Items Standard value
Oxygen sensor output voltage V 0.6 - 1.0
Oxygen sensor heater coil resistance (at 20_C) front 4.5 - 8.0
W
rear 11 - 18

MPI <4G6> - Troubleshooting
13A-4
TROUBLESHOOTING
DIAGNOSIS FUNCTION
ENGINE WARNING LAMP (CHECK ENGINE LAMP)
If an abnormality occurs in any of the following items related
to the MPI system, the engine warning lamp will illuminate
or flash. If the lamp remains illuminated or if the lamp
illuminates while the engine is running, check the diagnosis
code output.
However, the warning lamp will illuminate as bulb check for
five seconds whenever the ignition switch is turned to the
ON position.
Engine warning lamp inspection items
Code No. Diagnosis item
-Engine-ECU <M/T> or engine-A/T-ECU <A/T>
P0100 Air flow sensor system
P0105 Barometric pressure sensor system
P0110 Intake air temperature sensor system
P0115 Engine coolant temperature sensor system
P0120 Throttle position sensor system
P0125 Feedback system
P0130 Oxygen sensor (front) system <sensor 1>
P0135 Oxygen sensor heater (front) system <sensor 1>
P0136 Oxygen sensor (rear) system <sensor 2>
P0141 Oxygen sensor heater (rear) system <sensor 2>
P0170 Abnormal fuel system
P0201 No. 1 injector system
P0202 No. 2 injector system
P0203 No. 3 injector system
P0204 No. 4 injector system
P0300LIgnition coil (power transistor) system
P0301 No. 1 cylinder misfire detected
P0302 No. 2 cylinder misfire detected
P0303 No. 3 cylinder misfire detected
P0304 No. 4 cylinder misfire detected
P0335 Crank angle sensor system
P0340 Camshaft position sensor system
Engine warning lamp
(check engine lamp)

MPI <4G6> - Troubleshooting MPI <4G6> - Troubleshooting 13A-5
Code No. Diagnosis item
P0403 EGR valve system
P0420 Catalyst malfunction
P0443 Purge control solenoid valve system
P0505 Idle speed control system
P0510 Idle position switch system
P0551 Power steering fluid pressure switch system
NOTE
1. If the engine warning lamp illuminates because of a malfunction of the engine-ECU <M/T> or
engine-A/T-ECU <A/T>, communication between MUT-II and the engine-ECU <M/T> or engine-A/T-ECU
<A/T> is impossible. In this case, the diagnosis code cannot be read.
2. After the engine-ECU <M/T> or engine-A/T-ECU <A/T> 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.
3. After the engine warning lamp illuminates, it will be switched off under the following conditions.
(1) When the engine-ECU <M/T> or engine-A/T-ECU <A/T> 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.
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.

MPI <4G6> - Troubleshooting
13A-6
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-II and 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.
FREEZE FRAME DATA
When the engine-ECU <M/T> or engine-A/T-ECU <A/T>
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.
The display items of freeze frame data are shown below.
Display item list
Data item Unit
Engine coolant temperature sensor _C
Engine speed r/min
Vehicle speed km/h
Long-term fuel compensation (long-term
fuel trim)
%
Short-term fuel compensation (short-term
fuel trim)
%
Fuel control condi- Open loop OL
tion
Closed loop CL
Open loop owing to
drive condition
OL-DRV.
Open loop owing to
system malfunction
OL-SYS.
Closed loop based
on one oxygen sen-
sor
CL-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.

MPI <4G6> - Troubleshooting 13A-7
READINESS TEST STATUS
The engine-ECU <M/T> or engine-A/T-ECU <A/T> 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
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 item Control contents during malfunction
Air flow sensor 1. 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.
2. Fixes the ISC servo in the appointed position so idle control is not performed.
Intake air temperature
sensor
Controls as if the intake air temperature is 25_C.
Throttle position sen-
sor (TPS)
No increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant tem-
perature sensor
Controls as if the engine coolant temperature is 80_C.
Camshaft position
sensor
Injects fuel to all cylinders simultaneously.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre is not
detected at all.)
Barometric pressure
sensor
Controls as if the barometric pressure is 101 kPa.
Detonation sensor Switches the ignition timing from ignition timing for super petrol to ignition timing for standard
petrol.
Ignition coil, power
transistor
Cuts off the fuel supply to cylinders with an abnormal ignition.
Oxygen sensor (front) Air/fuel ratio feedback control (closed loop control) is not performed.
Oxygen sensor (rear) Performs the feedback control (closed loop control) of the air/fuel ratio by using only the
signal of the oxygen sensor (front) installed on the front of the catalytic converter.
Alternator FR terminal Does not control the output of the alternator according to an electrical load. (works as a
normal alternator)
Misfiring If the detected misfiring causes damage to the catalyst, the misfiring cylinder will be shut
down.

MPI <4G6> - Troubleshooting
13A-8
INSPECTION CHART FOR DIAGNOSIS CODES
Code No. Diagnosis item Reference page
P0100 Air flow sensor system 13A-10
P0105 Barometric pressure sensor system 13A-12
P0110 Intake air temperature sensor system 13A-14
P0115 Engine coolant temperature sensor system 13A-16
P0120 Throttle position sensor system 13A-18
P0125 Feedback system 13A-20
P0130 Oxygen sensor (front) system <sensor 1> 13A-21
P0135 Oxygen sensor heater (front) system <sensor 1> 13A-23
P0136 Oxygen sensor (rear) system <sensor 2> 13A-24
P0141 Oxygen sensor heater (rear) system <sensor 2> 13A-26
P0170 Abnormal fuel system 13A-27
P0201 No. 1 injector system 13A-28
P0202 No. 2 injector system 13A-28
P0203 No. 3 injector system 13A-28
P0204 No. 4 injector system 13A-28
P0300LIgnition coil (power transistor) system 13A-29
P0301 No. 1 cylinder misfire detected 13A-31
P0302 No. 2 cylinder misfire detected 13A-31
P0303 No. 3 cylinder misfire detected 13A-31
P0304 No. 4 cylinder misfire detected 13A-31
P0325 Detonation sensor system 13A-32
P0335 Crank angle sensor system 13A-32
P0340 Camshaft position sensor system 13A-34
P0403 EGR valve system 13A-36
P0420 Catalyst malfunction 13A-37
P0443 Purge control solenoid valve system 13A-38
P0500 Vehicle speed sensor system 13A-39
P0505 Idle speed control system 13A-39
P0510 Idle position switch system 13A-41
P0551 Power steering fluid pressure switch system 13A-42
P1500 Alternator FR terminal system 13A-43
P1610 Immobilizer system 13A-44

MPI <4G6> - Troubleshooting 13A-9
NOTE
1. Do not replace the engine-ECU <M/T> or engine-A/T-ECU <A/T> until a through terminal check reveals
there are no short/open circuit.
2. Check that the engine-ECU <M/T> or engine-A/T-ECU <A/T> earth circuit is normal before checking
for the cause of the problem.
3. After the engine-ECU <M/T> or engine-A/T-ECU <A/T> 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.

MPI <4G6> - Troubleshooting
13A-10
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No. P0100 Air flow sensor system Probable 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 <M/T>
DMalfunction of engine-A/T-ECU <A/T>
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
(3) NG Check the following connectors:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
To the next page
OK
Check the harness between the air
flow sensor and the engine control
relay, and repair if necessary.
(2) NG Check the following connector:
C-31
NG Repair
OK
Check the trouble symptoms.
NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG
Repair
NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
NG
Repair
OK
Check the following connector:
C-40 <M/T>, C-176 <A/T>
(1) NG Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
DIgnition switch: ON
DVoltage between terminal 90
<M/T>, 65 <A/T> and earth
OK: 4.8 - 5.2 V
OK
Measure at air flow sensor connector
B-12.
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
NG
Check the following connector:
B-12
NG
Repair
MUT-II Data list
12 Air flow sensor (Refer to
P.13A-75, DATA LIST
REFERENCE TABLE.)
OK Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)

MPI <4G6> - Troubleshooting 13A-11
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
Check the harnesses between the
air flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T> and
between the air flow sensor and the
engine control relay, and repair if
necessary.
OK
NG
Check the following connectors:
C-40 <M/T>, C-176 <A/T>, C-31
NG Repair
Check the trouble symptoms.
NG Replace the air flow sensor.
OK
Measure the output waveform at air
flow sensor connector B-12 (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-88 (In-
spection Procedure Using
an Analyzer) and noise
should not be displayed in
the waveform.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
NG Check the following connector:
C-34 <M/T>, C-177 <A/T>
NG Repair
OK
Measure at air flow sensor connector
B-12.
DUse test harness (MB991709) to
connect the connector, and
measure at the pick-up harness.
DVoltage between terminal 7 and
earth
OK: Engine: Idling
0-1V
Engine speed: 3,000 r/min
6-9V
OK
Replace the air flow sensor.
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
NG Check the following connector:
C-34 <M/T>, C-177 <A/T>
NG Repair
OK
Measure at air flow sensor connector
B-12.
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: 7-8V
From the previous page

MPI <4G6> - Troubleshooting
13A-12
Code No. P0105 Barometric pressure sensor system Probable cause
Range of Check
DTwo seconds have passed since the ignition switch is turned ON or the
engine starting process 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 <M/T>
DMalfunction of engine-A/T-ECU <A/T>
(2) NG Check the following connector:
C-40 <M/T>, C-176<A/T>
NG Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
MUT-II Data list
25 Barometric pressure sensor
(Refer to P.13A-75, DATA LIST
REFERENCE TABLE.)
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
NG Repair
OK
Measure at air flow sensor connector
B-12.
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) NG Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
DIgnition switch: ON
DVoltage between terminal 81
<M/T>, 46 <A/T> and earth
OK: 4.8 - 5.2 V
OK Check the following connectors:
C-40 <M/T>, C-176 <A/T>, C-47
<RHD>
NG
Repair
NG
Check the following connectors:
C-40 <M/T>, C-176 <A/T>, C-47
<RHD>
NG Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
To the next page
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
OK
Check the trouble symptoms. NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
Check the following connector:
B-12

MPI <4G6> - Troubleshooting 13A-13
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
From the previous page
OK
Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 85
<M/T>, 55 <A/T> and earth
OK: Altitude 0 m: 3.7 - 4.3 V
Altitude 1,200 m:
3.2 - 3.8 V
NG Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the trouble symptoms.
OK Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Measure at air flow sensor connector
B-12.
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 1,200 m:
3.2 - 3.8 V
(3) Voltage between terminal 5 and
earth
OK: 0.5 V or less
(1) NG Check the following connectors:
C-40 <M/T>, C-176 <A/T>, C-47
<RHD>
NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
(3) NG
(2) NG
Replace the air flow sensor.
NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG
Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
Check the trouble symptoms.

MPI <4G6> - Troubleshooting
13A-14
Code No. P0110 Intake air temperature sensor system Probable cause
Range of Check
DTwo seconds have passed since the ignition switch is turned ON or the
engine starting process 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 <M/T>
DMalfunction of engine-A/T-ECU <A/T>
OK
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
MUT-II Data list
13 Intake air temperature sensor
OK: Roughly the same as ambi-
ent temperature.
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG
Check the intake air temperature
sensor itself.
(Refer to P.13A-90*.)
NG Repair
OK
Measure at air flow sensor connector
B-12.
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 NG Repair
NG
Repair
NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG Repair
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the following connector:
B-12
NG Repair
(2) NG Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
DDisconnect connector B-12.
DIgnition switch: ON
DVoltage between terminal 62
<M/T>, 64 <A/T> and earth
OK: 4.8 - 5.2 V
OK Check the following connector:
C-40 <M/T>, C-176 <A/T>
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>.
NG
Repair
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
To the next page
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NOTE:
*: Refer to the ’97 GALANT Workshop Manual (Pub. No. PWDE9611)

MPI <4G6> - Troubleshooting 13A-15
OK
Measure at air flow sensor connector
B-12.
DUse the test harness (MB991709)
to connect only terminals 5 and
6, and then measure at the
pick-up 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 V
NG Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the harness between the air
flow sensor and the engine-ECU
<M/T> or engine-A/T-ECU <A/T>,
and repair if necessary.
OK
Check the trouble symptoms.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
From the previous page

MPI <4G6> - Troubleshooting MPI <4G6> - Troubleshooting
13A-16
Code No. P0115 Engine coolant temperature sensor
system
Probable cause
Range of Check
DEngine: Two seconds after the engine has been started
Set Conditions
DThe sensor output voltage is 4.6 V or more for four seconds (equivalent to
-45
_C or lower of engine coolant temperature)
or
DThe sensor output voltage is 0.1 V or less for four seconds (equivalent to
140_C or higher of engine coolant temperature)
DMalfunction of engine coolant temperature sensor
DOpen or short circuit in the engine coolant
temperature sensor circuit or loose connector
contact
DMalfunction of engine-ECU <M/T>
DMalfunction of engine-A/T-ECU <A/T>
Range of Check
DEngine: After starting
Set Conditions
DThe engine coolant temperature has reduced from over 40_C to less than
40_C, and that condition has lasted for five minutes or more.
OK
To the next page
MUT-II Data list
21 Engine coolant temperature
sensor
OK: When the engine is cold,
the temperature is roughly
the same as ambient tem-
perature. If warm, it is 80 -
120_C.
OK Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NG NG Replace
OK
Check the following connector:
B-33
NG Repair
Measure at engine coolant
temperature sensor connector B-33.
DDisconnect the connector and
measure at the harness side.
DResistance between terminals 1
and 2
OK: At 20_C of engine coolant
temperature: 2.1 - 2.7 kW
At 80_C of engine coolant
temperature: 0.26 - 0.36
kW

MPI <4G6> - Troubleshooting 13A-17
OK
Measure at engine coolant
temperature sensor connector B-33.
DUse test harness (MB991658) to
connect the connector, and
measure at the pick-up harness.
DIgnition switch: ON
DVoltage between terminal 1 and
earth
OK: At 0_C of engine coolant
temperature: 3.2 - 3.8 V
At 20_C of engine coolant
temperature: 2.3 - 2.9 V
At 40_C of engine coolant
temperature: 1.3 - 1.9 V
At 80_C of engine coolant
temperature: 0.3 - 0.9 V
NG Check the engine coolant
temperature sensor.
(Refer to P.13A-90*.)
NG Repair
OK
Check the harness wire between the
engine coolant temperature sensor
and the engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the harness wire between the
engine coolant temperature sensor
and the engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
OK
Measure at engine coolant
temperature sensor connector B-33.
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 2
and earth
OK: 2Wor less
(1) NG Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
DDisconnect connector B-33.
DIgnition switch: ON
DVoltage between terminal 83
<M/T>, 44 <A/T> and earth
OK: 4.8 - 5.2 V
OK Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG
Repair
NG
NG Repair
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
(2) NG
OK
Repair
OK
Check the harness wire between the
engine coolant temperature sensor
and the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
NG Repair
NG
Check the harness wire between the
engine coolant temperature sensor
and the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
NG Repair
OK
Check the trouble symptoms. NG Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
Check the following connector:
C-40 <M/T>, C-176 <A/T>
Check the following connector:
C-40 <M/T>, C-176 <A/T>
From the previous page
NOTE:
*: Refer to the ’97 GALANT Workshop Manual (Pub. No. PWDE9611)

MPI <4G6> - Troubleshooting
13A-18
Code No. P0120 Throttle position sensor system Probable cause
Range of Check
DExcluding two seconds after the ignition switch is turned ON or immediately
after the engine starts.
Set Conditions
DWhen the idle position switch is ON, the sensor output voltage is 2 V or
more for 4 seconds
or
DThe sensor output voltage is 0.2 V or less for 4 seconds
DMalfunction of throttle position sensor
DImproper connector contact, open circuit or
short-circuited harness wire
DImproper “ON” state of idle position switch
DShort circuit of the idle position switch signal line
DMalfunction of engine-ECU <M/T>
DMalfunction of engine-A/T-ECU <A/T>
OK
Check the trouble symptoms.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
To the next page
OK
Check the trouble symptoms.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
NG Repair
NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG
Repair
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
NG
Repair
OK
Measure at throttle position sensor
connector B-07.
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 4
and earth
OK: 2Wor less
(1) NG Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-176 <A/T>.
DMeasure the voltage at the
engine-ECU <M/T> or
engine-A/T-ECU <A/T> connector
terminals.
DIgnition switch: ON
DVoltage between terminal 81 and
earth
OK: 4.8 - 5.2 V
OK Check the following connector:
C-40 <M/T>, C-176 <A/T>
(2) NG Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
NG
Repair
OK
Check the following connector:
B-07
NG Repair
NG
Check the throttle position sensor.
(Refer to P.13A-91*.)
NG Replace
MUT-II Data list
14 Throttle position sensor
(Refer to P.13A-75, DATA LIST
REFERENCE TABLE.)
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
NOTE:
*: Refer to the ’97 GALANT Workshop Manual (Pub. No. PWDE9611)

MPI <4G6> - Troubleshooting 13A-19
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
OK Check the following connector:
C-40 <M/T>, C-175<A/T>
NG Repair
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-175 <A/T>.
DMeasure voltage at the
engine-ECU terminal.
DIgnition switch: ON
DVoltage between terminal 84
<M/T>, 78 <A/T> and earth
OK: Accelerator pedal fully re-
leased: 0.3 - 1.0 V
Accelerator pedal fully de-
pressed: 4.5 - 5.5 V
NG Check the following connector:
C-40 <M/T>, C-175 <A/T>
NG
Repair
OK
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
Check the following connector:
C-40 <M/T>, C-175 <A/T>
NG Repair
(3) NG Adjust the throttle position sensor.
(Refer to P.13A-81*.)
OK
Check the harness wire between the
throttle position sensor and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
(1) NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG Repair
(2) NG
OK
Measure at throttle position sensor
connector B-07.
DUse test harness (MB991536) to
connect the connector, 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 4 and
earth
OK: 0.5 V or less
(3) Voltage between terminal 2 and
earth
OK: Accelerator pedal fully re-
leased: 0.3 - 1.0 V
Accelerator pedal fully de-
pressed: 4.5 - 5.5 V
From the previous page
NOTE:
*: Refer to the ’97 GALANT Workshop Manual (Pub. No. PWDE9611)

MPI <4G6> - Troubleshooting
13A-20
Code No. P0125 Feedback system Probable cause
Range of Check
DThe engine coolant temperature is approx. 80_C or more.
DDuring stoichiometric feedback control
DThe vehicle is not being decelerated.
Set Conditions
DOxygen sensor (front) output voltage has been higher or lower 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 <M/T>
DMalfunction of engine-A/T-ECU <A/T>
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
OK
Transient malfunction
(Refer to GROUP 00 - Points to
Note for Intermittent Malfunctions.)
OK
Check the following connector:
C-40 <M/T>, C-175 <A/T>
Repair
NG
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
NG Check the following connector:
C-40 <M/T>, C-175 <A/T>
NG Repair
OK
Measure at engine-ECU connector
C-40 <M/T> or engine-A/T-ECU
connector C-175 <A/T>.
DMeasure the voltage at the
engine-ECU terminal <M/T> or
engine-A/T-ECU terminal <A/T>.
DEngine: 2,500 r/min (after
warming up)
DVoltage between terminal 76
<M/T>, 71 <A/T> and earth
OK: 0 V and 0.8 V alternate.
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
OK NG Repair
Check the following connector:
C-40 <M/T>, C-175 <A/T>
(2) NG Check the oxygen sensor (front).
(Refer to P.13A-89.)
NG Replace
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>, and repair if
necessary.
Repair
(1) NG
Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG
OK
Measure at oxygen sensor (front)
connector C-46.
DMeasure the voltage at the
oxygen sensor (front) terminal
DEngine: 2,500 r/min (after
warming up)
(1) Voltage between terminal 2 and
earth
OK: 0.5 V or less
(2) Voltage between terminal 1 and
earth
OK: 0 V and 0.8 V alternate.
NG
Replace the engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
OK
Check the trouble symptoms.
OK
Check the harness wire between the
oxygen sensor (front) and the
engine-ECU <M/T> or
engine-A/T-ECU <A/T>.
NG Repair
Repair
OK
Measure at oxygen sensor (front)
connector C-46.
DDisconnect the connector and
measure at the harness side.
DResistance between terminal 2
and earth
OK: 2Wor less
NG Check the following connector:
C-40 <M/T>, C-176 <A/T>
NG
Check the following connector:
C-46
NG Repair