Mitsubishi Eclipse / Eclipse Spyder (2000-2002). Service and repair manual — part 237

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-147

DTC P0141: O

2

Sensor Heater Circuit Malfunction (bank 1 sensor 2)

AK000693

3 4

1 2

RED-

WHITE

RED-

WHITE

RED-

WHITE

RED

BR

O

W

N

3 4

1 2

BATTERY

A-21X

MFI
RELAY

RIGHT BANK HEATED
OXYGEN SENSOR(REAR)

TO ECM
OR PCM

TO ECM
OR PCM

1

2

3

4

4

2

1

3

ENGINE CONTROL
MODULE(ECM)<M/T>
OR
POWERTRAIN CONTROL
MODULE(PCM)<A/T>

27

B-28
MU802665

C-51<M/T>,C-52<A/T>
(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 ENGINE>

13B-148

CIRCUIT OPERATION

•

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

•

The ECM (terminal 27) <M/T> or PCM (terminal
27) <A/T> controls continuity to the right bank
heated oxygen sensor (rear) heater by turning
the power transistor in the ECM <M/T> or PCM
<A/T> "ON" and "OFF."

BACKGROUND

•

The ECM <M/T> or PCM <A/T> 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 right bank heated oxygen sensor (rear)
heater is on.

•

Battery positive voltage is at between 11 and 16
volts.

Judgment Criteria

•

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

•

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

•

ECM failed. <M/T>

•

PCM failed. <A/T>

DIAGNOSIS

Required Special Tools
MB991316: Test Harness

ACX02493AC

CONNECTOR : B-28

RIGHT BANK
HEATED OXYGEN
SENSOR(REAR)

AK000226

AK000226AB

CONNECTOR : A-21X

MFI RELAY

AK000225

CONNECTOR : C-51<M/T>, C-52<A/T>

C-52

C-51

PCM<A/T>

ECM<M/T>

AJ

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-149

STEP 1. Check connector B-28 at the right 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 right bank heated oxygen sensor (rear).
(1) Disconnect right bank heated oxygen sensor (rear)

connector B-28 and connect test harness special tool,
MB991316, to the connector on the right 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 right bank heated oxygen sensor (rear).

Then go to Step 12.

STEP 3. Check the power supply voltage at right bank
heated oxygen sensor (rear) harness side connector B-28.
(1) Disconnect the connector B-28 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.

AK000211

CONNECTOR : B-28

AB

ACX02493AC

CONNECTOR : B-28

RIGHT BANK
HEATED OXYGEN
SENSOR(REAR)

AKX01624 AB

MB991316

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

BLUE

RED

AKX01496AE

B-28 HARNESS
SIDE CONNECTOR

1

4

3

2

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-150

STEP 4. Check harness 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 right bank heated oxygen sensor
(rear) connector B-28 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 ECM connector
C-51 <M/T> or PCM connector C-52 <A/T> by backprobing.
(1) Do not disconnect the connector C-51 <M/T> or C-52 <A/

T>.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 27 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-51 at ECM <M/T> or connector
C-52 at PCM <A/T> 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.

AK000226

AK000226AB

CONNECTOR : A-21X

MFI RELAY

AKX01537

AKX01537

1

2

3 4

5 6

7 8

9

10 11 12 13 14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

C-51<M/T>, C-52<A/T>
CONNECTOR HARNESS
SIDE VIEW

AF

AK000225

CONNECTOR : C-51<M/T>, C-52<A/T>

C-52

C-51

PCM<A/T>

ECM<M/T>

AJ