Mitsubishi Galant. Manual — part 229

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-141

DTC P0139: O

2

Sensor Circuit Slow Response (bank 1 sensor 2)

AK000503

BLA

CK

BLA

CK

YELLO

W

3 4

1 2

FROM MFI RELAY

RIGHT BANK HEATED
OXYGEN SENSOR(REAR)

TO ECM
OR PCM

74

57

1

3

2

4

B-31
MU802665

POWERTRAIN CONTROL
MODULE(PCM)

C-40
(MU803781)

42 43
48 49 50 51 52 53 54 55 56 57

46

45

44

58 59

60 61 62 63

64 65 66

47

41

98

78

71

88 89

76 77

72
79
91

73
80

74

75

81
92

82 83
93

84 85

94

86 87

95 96

90

97

C-41
(MU803782)

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-142

CIRCUIT OPERATION

•

A voltage corresponding to the oxygen
concentration in the exhaust gas is sent to the
PCM (terminal 74) from the output terminal
(terminal 4) of the right bank heated oxygen
sensor (rear).

•

Terminal 2 of the right bank heated oxygen
sensor (rear) is grounded with PCM (terminal 57).

TECHNICAL DESCRIPTION

•

The output signal of the right bank heated oxygen
sensor (front) is compensated by the output
signal of the right bank heated oxygen sensor
(rear).

•

The PCM checks for an open circuit in the right
bank heated oxygen sensor (rear) output line.

DTC SET CONDITIONS

Check Conditions

•

Engine coolant temperature is higher than 82

°

C

(180

°

F).

•

Barometric pressure is higher than 76 kPa (11
psi).

•

The right bank heated oxygen sensor (front) is
active.

Judgement Criteria

•

The right bank heated oxygen sensor (rear)
output voltage, before the fuel shut off is started,
was 0.4 volts or more, and during the shut off, it
takes one second or more for the right bank
heated oxygen sensor (rear) output voltage to fall
from 0.4 to 0.15 volts.

or

•

The right bank heated oxygen sensor (rear)
output voltage, before the fuel shut off is started,
was 0.15 volts or more, and during the shut off, it
takes three seconds or more for the right bank
heated oxygen sensor (rear) output voltage to fall
below 0.15 volts.

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

•

Right bank heated oxygen sensor (rear) failed.

•

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

•

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

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB991502: Scan Tool (MUT-II)

ACX02493AG

CONNECTOR:B-31

RIGHT BANK
HEATED OXYGEN
SENSOR (REAR)

AK000280

CONNECTORS : C-40, C-41

C-41

C-40

PCM

AX

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-143

STEP 1. Using scan tool MB991502, check data list item 69:
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

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

69, Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

(4) Warm up the engine.

•

After increasing the output voltage 0.15 volts or more by
the engine revving, finish it. Then confirm that the output
voltage reduces to 0.15 volts or less within 3 seconds.

(5) 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 right bank heated oxygen sensor (rear).

Then go to Step 2.

STEP 2. 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 P0139 is output?

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

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-144

DTC P0141: O

2

Sensor Heater Circuit Malfunction (bank 1 sensor 2)

AK000504

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

POWERTRAIN CONTROL
MODULE(PCM)

27

B-31
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