Mitsubishi Galant. Manual — part 232

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-153

STEP 1. Using scan tool MB991502, check data list item 11:
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK"(OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

11, Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

•

Warming up the engine. When the engine is revved, the
output voltage should be 0.6 to 1.0 volt.

•

Warming up the engine. When the engine is idling, the
output voltage should repeat 0.4 volt and 0.6 to 1.0 volt
alternately.

(4) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points(

P.00-8

).

NO : Go to Step 2.

STEP 2. Check the sensor output voltage at left bank
heated oxygen sensor (front) connector B-28 by
backprobing.
(1) Do not disconnect the connector B-28.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal 4 and ground by

backprobing.

•

Warming up the engine. When the engine is 2,500 r/min,
the output voltage should repeat 0 to 0.8 volt alternately.

(4) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the voltage normal?

YES : Go to Step 3.
NO : Go to Step 7.

STEP 3. Check the sensor output voltage at PCM
connector C-41 by backprobing.
(1) Do not disconnect the connector C-41.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal 71 and ground by

backprobing.

•

Warming up the engine. When the engine is 2,500 r/min,
the output voltage should repeat 0 to 0.8 volt alternately.

(4) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the voltage normal?

YES : Go to Step 4.
NO : Go to Step 6.

AC003081 AB

16 PIN

MB991502

AKX01541

B-28 CONNECTOR
HARNESS SIDE VIEW

2

4

1

3

AJ

AKX01539

AKX01539

717273 74

78 7980 818283 8485 86 87 88 89

75 76 77

98

97

96

95

94

93

92

91

90

C-41 CONNECTOR
HARNESS SIDE VIEW

AE

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-154

STEP 4. Check connector B-28 at left bank heated oxygen
sensor (front) and connector C-41 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 5.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 15.

STEP 5. Using scan tool MB991502, check data list item 11:
Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK"(OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at idle.
(3) Set scan tool MB991502 to the data reading mode for item

11, Heated Oxygen Sensor Bank 2, Sensor 1 (left front).

•

Warming up the engine. When the engine is revved, the
output voltage should be 0.6 to 1.0 volt.

•

Warming up the engine. When the engine is idling, the
output voltage should repeat 0.4 volt and 0.6 to 1.0 volt
alternately.

(4) Turn the ignition switch to the "LOCK"(OFF) position.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points(

P.00-8

).

NO : Replace the PCM. Then go to Step 15.

AK000619

CONNECTOR:B-28

AB

AK000280

CONNECTOR : C-41

PCM

AY

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-155

STEP 6. Check connector B-28 at left bank heated oxygen
sensor (front) and connector C-41 at PCM for damage.
Q: Is the connector in good condition?

YES : Repair harness wire between left bank heated oxygen

sensor (front) connector B-28 terminal 4 and PCM
connector C-41 terminal 71 because of open circuit or
harness damage. Then go to Step 15.

NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 15.

STEP 7. Check connector B-28 at left bank heated oxygen
sensor (front) for damage.
Q: Is the connector in good condition?

YES : Go to Step 8.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 15.

STEP 8. Check the continuity at left bank heated oxygen
sensor (front) harness side connector B-28.
(1) Disconnect the connector B-28 and measure at the harness

side.

(2) Check for the continuity between terminal 2 and ground.

•

Should be less than 2 ohm.

Q: Is the continuity normal?

YES : Go to Step 11.
NO : Go to Step 9.

AK000619

CONNECTOR:B-28

AB

AK000280

CONNECTOR : C-41

PCM

AY

AK000619

CONNECTOR:B-28

AB

AK000239

B-28 HARNESS
SIDE CONNECTOR

2

4

1

3

AI

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-156

STEP 9. Check connector C-40 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 10.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then go to Step 15.

STEP 10. Check for open circuit and harness damage
between left bank heated oxygen sensor (front) connector
B-28 terminal 2 and PCM connector C-40 terminal 57.
Q: Is the harness wire in good condition?

YES : Replace the PCM. Then go to Step 15.
NO : Repair it. Then go to Step 15.

STEP 11. Check connector C-41 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 12.
NO : Repair or replace it. Then go to Step 15.

AK000280

CONNECTOR : C-40

PCM

AV

AK000619

CONNECTOR:B-28

AB

AK000280

CONNECTOR : C-40

PCM

AV

AK000280

CONNECTOR : C-41

PCM

AY