Mitsubishi Galant. Manual — part 235

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-165

STEP 8. Check for harness damage between left bank
heated oxygen sensor (front) connector B-28 terminal 4
and PCM connector C-41 terminal 71.
Q: Is the harness wire in good condition?

YES : Go to Step 9.
NO : Repair it. Then go to Step 11.

STEP 9. Check for harness damage between left bank
injector connector and PCM connector.

a. Check the harness wire between injector connector B-21

terminal 2 and PCM connector C-39 terminal 9when
checking No.2 cylinder.

b. Check the harness wire between injector connector B-17

terminal 2 and PCM connector C-39 terminal 2 when
checking No.4 cylinder.

c. Check the harness wire between injector connector B-30

terminal 2 and PCM connector C-39 terminal 25 when
checking No.6 cylinder.

Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO : Repair it. Then go to Step 11.

AK000619

CONNECTOR:B-28

AB

AK000280

CONNECTOR : C-41

PCM

AY

AK000618 AD

CONNECTORS:B-17,B-21,B-30

B-30

B-17

B-21

AK000280

CONNECTOR : C-39

PCM

AW

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-166

STEP 10. Check the fuel pressure.
Refer to, Fuel Pressure Test(

P.13B-522

).

Q: Is the fuel pressure normal?

YES : Replace the PCM. Then go to Step 11.
NO : Repair or replace it. Then go to Step 11.

STEP 11. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to,

Procedure 6

−

Other Monitor(

P.13B-4

).

(2) Check the diagnostic trouble code (DTC).

Q: Is the DTC P0154 is output?

YES : Retry the troubleshooting.
NO : The inspection is complete.

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-167

DTC P0155: O

2

Sensor Heater Circuit Malfunction (bank 2 sensor 1)

AK000506

3 4

1 2

3 4

1 2

RED-

WHITE

RED-

WHITE

RED-

WHITE

RED

BR

O

WN-WHITE

BATTERY

A-21X

3

4

1

2

LEFT BANK HEATED
OXYGEN SENSOR(FRONT)

B-28
MU802605

1

2

3

4

TO ECM
OR PCM

TO ECM
OR PCM

POWERTRAIN CONTROL
MODULE(PCM)

3

MFI
RELAY

C-39
(MU803784)

2

3 4

5 6

7 8

9

11 12 13 14 15 16 17 18 19 20

30

21 22 23

24 25

26 27 28 29

3132 33

34 35

1

10

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-168

CIRCUIT OPERATION

•

Power is supplied from the MFI relay (terminal 1)
to the left bank heated oxygen sensor (front)
heater.

•

The PCM (terminal 3) controls continuity to the
left bank heated oxygen sensor (front) heater by
turning the power transistor in the PCM "ON" and
"OFF."

TECHNICAL DESCRIPTION

•

The PCM checks whether the heater current is
within a specified range when the heater is
energized.

DTC SET CONDITIONS

Check Conditions

•

Engine coolant temperature is higher than 20

°

C

(68

°

F).

•

While the left bank heated oxygen sensor (front)
heater is on.

•

Battery positive voltage is at between 11 and 16
volts.

Judgment Criteria

•

Heater current of the left bank heated oxygen
sensor (front) heater has continued to be lower
than 0.2 ampere or higher than 3.5 ampere for 6
seconds.

•

Only one monitor during one drive cycle

TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)

•

Open or shorted left bank heated oxygen sensor
(front) heater circuit.

•

Open circuit in left bank heated oxygen sensor
(front) heater.

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB998464: Test Harness Set

ACX02489 AF

CONNECTOR:B-28

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK000555AB

CONNECTOR : A-21X

MFI RELAY

AK000280

CONNECTOR : C-39

PCM

AW