Mitsubishi Galant. Manual - part 233

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-157

STEP 12. Check for harness damage between left bank
heated oxygen sensor (front) connector B-28 terminal 2
and PCM connector C-40 terminal 57.
Q: Is the harness wire in good condition?

YES : Go to Step 13.
NO : Repair it. Then go to Step 15.

STEP 13. Check for short circuit to ground and 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 14.
NO : Repair it. Then go to Step 15.

AK000619

CONNECTOR:B-28

AK000280

CONNECTOR : C-40

PCM

AK000619

CONNECTOR:B-28

AK000280

CONNECTOR : C-41

PCM

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-158

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

connector B-28 and connect test harness special tool,
MD998464, 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 (front).
(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 (front) 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 (front).

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 P0150 is output?

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

ACX02489 AF

CONNECTOR:B-28

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-159

DTC P0153: O

Sensor Circuit Slow Response (bank 2 sensor 1)

AK000505

1 2
3

BLA

WHITE

B-28
MU802605

POWERTRAIN CONTROL
MODULE(PCM)

LEFT BANK HEATED OXYGEN
SENSOR(FRONT)

FROM MFI RELAY

TO ECM
OR PCM

88 89

76 77

72
79
91

73
80

81
92

82 83
93

84 85

86 87

95 96

C-41
(MU803782)

C-40
(MU803781)

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

58 59

60 61 62 63

64 65 66

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-160

CIRCUIT OPERATION

•

A voltage corresponding to the oxygen
concentration in the exhaust gas is sent to the
PCM (terminal 71) from the output terminal
(terminal 4) of the left bank heated oxygen sensor
(front).

•

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

TECHNICAL DESCRIPTION

•

The left bank heated oxygen sensor (front)
detects the concentration of oxygen in the
exhaust gas; it converts that data to voltage, and
sends it to the PCM.

•

When the left bank heated oxygen sensor (front)
begins to deteriorate, the heated oxygen sensor
signal response deteriorates also.

•

The PCM varies the air/fuel mixture to make it
leaner and richer, and checks the response
speed of the left bank heated oxygen sensor
(front). In addition, the PCM also checks for an
open circuit in the left bank heated oxygen sensor
(front) output line.

DTC SET CONDITIONS

Check Conditions

•

Engine coolant temperature is higher than 50

(176

F).

•

Engine speed is at between 1,250 and 3,000 r/
min.

•

Volumetric efficiency is at between 20 and 60
percent.

•

Intake air temperature is higher than -10

C (14

F).

•

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

•

Under the closed loop air/fuel control.

•

PCM dose not judge to be idling state.

Judgment Criteria

•

The left bank heated oxygen sensor (front) sends
"lean" and "rich" signals alternately 10 times
(Response time 1.2 or equivalent) or less for 12
seconds.

•

Only one monitor during one drive cycle

NOTE: If the sensor switch time is longer than the
Judgment Criteria due to the MUT-II OBD-II test
Mode

−

H02S Test Results, it is assumed that the

heated oxygen sensor has deteriorated. If it is
short, it is assumed that the harness wire is
broken or has a short circuit.
If the heated oxygen sensor signal voltage has
not changed even once (lean/rich) after the DTC
was erased, the sensor switch time will display as
0 seconds.

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

•

Left bank heated oxygen sensor (front)
deteriorated.

•

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

•

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

•

PCM failed.

DIAGNOSIS

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

ACX02489 AF

CONNECTOR:B-28

LEFT BANK
HEATED OXYGEN
SENSOR (FRONT)

AK000280

CONNECTORS : C-40, C-41

C-41

C-40

PCM

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