Mitsubishi Galant. Manual — part 240

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-185

DTC P0161: O

2

Sensor Heater Circuit Malfunction (bank 2 sensor 2)

AK000508

3 4

1 2

RED-

WHITE

RED-

WHITE

RED-

WHITE

RED

BLUE-RED

3 4

1 2

BATTERY

A-21X

MFI
RELAY

LEFT BANK HEATED
OXYGEN SENSOR(REAR)

TO ECM
OR PCM

TO ECM
OR PCM

1

2

3

4

4

2

1

3

POWERTRAIN CONTROL
MODULE(PCM)

26

B-29
MU802665

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-186

CIRCUIT OPERATION

•

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

•

The PCM (terminal 26) controls continuity to the
left bank heated oxygen sensor (rear) heater by
turning the power transistor in the PCM "ON" and
"OFF."

BACKGROUND

•

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 (rear)
heater is on.

•

Battery positive voltage is between 11 and 16
volts.

Judgment Criteria

•

Heater current of the left bank heated oxygen
sensor (rear) 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
(rear) heater circuit.

•

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

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB991316: Test Harness Set

ACX02488

CONNECTOR:B-29

LEFT BANK
HEATED OXYGEN
SENSOR(REAR)

AG

AK000555AB

CONNECTOR : A-21X

MFI RELAY

AK000280

CONNECTOR : C-39

PCM

AW

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-187

STEP 1. Check connector B-29 at the left bank heated
oxygen sensor (rear) for damage.
Q: Is the connector in good condition?

YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection (

P.00E-2

). Then go to Step 12.

STEP 2. Check the left bank heated oxygen sensor (rear).
(1) Disconnect left bank heated oxygen sensor (rear)

connector B-29 and connect test harness special tool,
MB991316, to the connector on the left bank heated oxygen
(rear) sensor side.

(2) Measure the resistance between heated oxygen sensor

connector terminal 1 (red clip) and terminal 3 (blue clip).

Standard value: 11

−−−−

18 ohm [at 20

°°°°

C (68

°°°°

F)]

Q: Is the resistance normal?

YES : Go to Step 3.
NO : Replace the left bank heated oxygen sensor (rear).

Then go to Step 12.

STEP 3. Check the power supply voltage at left bank
heated oxygen sensor (rear) harness side connector B-29.
(1) Disconnect the connector B-29 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 1 and ground.

•

Voltage should be battery positive voltage.

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

Q: Is the voltage normal?

YES : Go to Step 5.
NO : Go to Step 4.

AK000619 AC

CONNECTOR:B-29

ACX02488

CONNECTOR:B-29

LEFT BANK
HEATED OXYGEN
SENSOR(REAR)

AG

AKX01624 AB

MB991316

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

BLUE

RED

AKX01496

B-29 HARNESS
SIDE CONNECTOR

2

4

1

3

AH

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-188

STEP 4. Check connector A-21X at the MFI relay for
damage.
Q: Is the connector in good condition?

YES : Repair harness wire between MFI relay connector A-

21X terminal 1 and left bank heated oxygen sensor
(rear) connector B-29 terminal 1 because of open
circuit or short circuit to ground. Then go to Step 12.

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

Connector Inspection (

P.00E-2

). Then go to Step 12.

STEP 5. Check the power supply voltage at PCM connector
C-39 by backprobing.
(1) Do not disconnect the connector C-39.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 26 and ground by

backprobing.

•

Voltage should be battery positive voltage.

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

Q: Is the voltage normal?

YES : Go to Step 8.
NO : Go to Step 6.

STEP 6. Check connector C-39 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 7.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection (

P.00E-2

). Then go to Step 12.

AK000555AB

CONNECTOR : A-21X

MFI RELAY

AKX01543

AKX01543

1

2

3 4

5 6

7 8

9 10 1112 13 141516 1718 19 20 212223

24 25

26 2728 29

303132 33

3435

AE

C-39 CONNECTOR
HARNESS SIDE VIEW

AK000280

CONNECTOR : C-39

PCM

AW