Mitsubishi Galant. Manual — part 239

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-181

STEP 14. Check the left bank heated oxygen sensor (rear).
(1) Disconnect the 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
sensor (front) side.

(2) Warm up the engine until engine coolant 80

°

C (176

°

F) or

higher.

CAUTION

Be very careful when connecting the jumper wires;
incorrect connection can damage the left bank heated
oxygen sensor (rear).
(3) Use the jumper wires to connect terminal 1 (red clip) to the

positive battery terminal and terminal 3 (blue clip) to the
negative battery terminal.

(4) Connect a digital volt meter between terminal 2 (black clip)

and terminal 4 (white clip).

(5) While repeatedly revving the engine, measure the left bank

heated oxygen sensor (rear) output voltage.

Standard value: 0.6

−−−−

1.0 V

Q: Is the voltage at the standard value?

YES : Replace the PCM. Then go to Step 15.
NO : Replace the left bank heated oxygen sensor (rear).

Then go to Step 15.

STEP 15. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to,

Procedure 4

−

Heated oxygen Sensor Monitor and

Procedure 6

−

Other Monitor (

P.13B-4

).

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

Q: Is the DTC P0156 is output?

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

ACX02488

CONNECTOR:B-29

LEFT BANK
HEATED OXYGEN
SENSOR(REAR)

AG

AKX01625 AB

BLUE

JUMPER
WIRES

BLACK

RED

WHITE

MB991316

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-182

DTC P0159: O

2

Sensor Circuit Slow Response (bank 2 sensor 2)

AK000507

BLA

CK

BLA

CK

GREEN

3 4

1 2

FROM MFI RELAY

LEFT BANK HEATED
OXYGEN SENSOR(REAR)

TO ECM
OR PCM

73

57

1

3

2

4

B-29
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-183

CIRCUIT OPERATION

•

A voltage corresponding to the oxygen
concentration in the exhaust gas is sent to the
PCM (terminal 73) from the output terminal
(terminal 4) of the left bank heated oxygen sensor
(rear).

•

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

TECHNICAL DESCRIPTION

•

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

•

The PCM checks for an open circuit in the left
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 left bank heated oxygen sensor (front) is
active.

Judgement Criteria

•

The 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 heated oxygen sensor (rear)
output voltage to fall from 0.4 to 0.15 volts.

or

•

The 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 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:)

•

Left bank heated oxygen sensor (rear) failed.

•

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

•

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

•

PCM failed.

DIAGNOSIS

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

ACX02488

CONNECTOR:B-29

LEFT BANK
HEATED OXYGEN
SENSOR(REAR)

AG

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-184

STEP 1. Using scan tool MB991502, check data list item 59:
Heated Oxygen Sensor Bank 2, Sensor 2 (left 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

59, Heated Oxygen Sensor Bank 2, Sensor 2 (left 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 left 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 P0159 is output?

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

AC003081 AB

16 PIN

MB991502