Mitsubishi Galant. Manual — part 220

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-105

STEP 10. Using scan tool MB991502, check data list item
14: Throttle Position Sensor.

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) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 to the data reading mode for item

14, Throttle Position Sensor.

•

With the throttle valve in the idle position, voltage should
be between 0.535 and 0.735 volts.

•

With the throttle valve in the full-open position, voltage
should be between 4.5 and 5.5 volts.

(4) 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 PCM. Then go to Step 11.

STEP 11. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to

P.13B-4

, Procedure 6

−

Other Monitor.

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

Q: Is the DTC P0123 is output?

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

DTC P0128: Coolant Thermostat Malfunction

TECHNICAL DESCRIPTION

•

The PCM checks the time for the engine coolant
temperature to reach the judgment temperature.

DTC SET CONDITIONS

Check Area

•

Engine coolant temperature is between -10

°

C

(14

°

F) and 82

°

C (180

°

F) when the engine is

started.

•

The engine coolant temperature

−

intake air

temperature is 5

°

C (48

°

F) or less when the

engine is started.

•

The intake air temperature when the engine is
started

−

intake air temperature is 2

°

C (36

°

F) or

less.

•

The volume air flow sensors output frequency is
in the low frequency (50-100Hz or less) state for
300 seconds or less.

Judgment Criteria

•

The time for the engine coolant temperature to
rise to 82

°

C (180

°

F) takes longer than the

specified time *.
*: Approximately 11 to 23 minutes when the

engine coolant temperature at start is 20

°

C

(68

°

F) or more.

Approximately 20 to 54 minutes when the

engine coolant temperature at start is 20

°

C

(68

°

F) or less.

•

Only one monitor during one drive cycle.

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

•

The thermostat is faulty

•

PCM failed.

AC003081 AB

16 PIN

MB991502

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-106

DIAGNOSIS

STEP 1. Check the cooling system.
Refer to GROUP 14, Engine Cooling Diagnosis(

P.14-2

).

Q: Is the cooling system normal?

YES : Replace the PCM. Then check that the DTC P0128

does not reset.

NO : Repair it. Then check that the DTC P0128 does not

reset.

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-107

DTC P0130: O

2

Sensor Circuit Malfunction (bank 1 sensor 1)

AK000501

4

1 2

3

BLA

CK

BLA

CK

BLUE

B-33
MU802605

POWERTRAIN CONTROL
MODULE(PCM)

RIGHT BANK HEATED OXYGEN
SENSOR(FRONT)

FROM MFI RELAY

TO ECM
OR PCM

1

2

3

4

57

72

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)

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

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-108

CIRCUIT OPERATION

•

A voltage corresponding to the oxygen
concentration in the exhaust gas is sent to the
PCM (terminal 72) from the output terminal
(terminal 4) of the right bank heated oxygen
sensor (front).

•

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

TECHNICAL DESCRIPTION

•

The right bank heated oxygen sensor (front)
detects the concentration of oxygen in the
exhaust gas; it converts those data to voltage,
and inputs the resulting signals to the PCM.

•

When the right bank heated oxygen sensor
(front) begins to deteriorate, the heated oxygen
sensor signal response becomes poor.

•

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

DTC SET CONDITIONS

Check Conditions

•

Right bank heated oxygen sensor (front) signal
voltage has continued to be 0.2 volt or lower for
three minutes or more after the starting sequence
was completed.

•

Engine coolant temperature is higher than 82

°

C

(180

°

F).

•

Engine speed is higher than 1,200 r/min.

•

Volumetric efficiency is higher than 25 percent.

•

Monitoring time: 7 seconds.

Judgment Criteria

•

Input voltage supplied to the PCM interface
circuit is higher than 4.5 volts when 5 volts is
applied to the right bank heated oxygen sensor
(front) output line via a resistor.

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

•

Right bank heated oxygen sensor (front)
deteriorated.

•

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

•

Open circuit in right black heated oxygen sensor
(front) ground line.

•

PCM failed.

DIAGNOSIS

Required Special Tools
MB991502: Scan Tool (MUT-II)
MD998464: Test Harness

ACX02481AG

CONNECTOR:B-33

RIGHT BANNK
HEATED OXYGEN
SENSOR(FRONT)

AK000280

CONNECTORS : C-40, C-41

C-41

C-40

PCM

AX