Mitsubishi Galant (2004+). Manual - part 1089

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-49

STEP 7. Check for harness damage between mass airflow 
sensor connector B-10 (terminal No. 3) and PCM connector 
B-22 (terminal No. 108).
Q: Is the harness wire in good condition?

YES : Go to Step 8.
NO :  Repair it. Then go to Step 9.

STEP 8. Replace the mass airflow sensor.
(1) Replace the mass airflow sensor.
(2) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor 

P.13B-5

.

(3) Check the diagnostic trouble code (DTC).
Q: Is DTC P0101 set?

YES : Replace the PCM. Then go to Step 9.
NO :  The inspection is complete.

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

AK303018

55

56

54 53 52 51

57

62 61 60 59 58

63

69 68 67 66 65 64

70

75 74 73 72 71

76

82 81 80 79 78 77

83

CONNECTOR: B-21

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER

B-21 (B)

AK303015

2

1

3

4

AB

B-10 (GR)

CONNECTOR: B-10

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-50

STEP 9. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 6 − 

Other Monitor 

P.13B-5

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0101 set?

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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-51

DTC P0102: Mass Airflow Circuit Low In put

CAUTION

If DTC P0102 has been set, TCL related DTC 
U1120 is also set. After P0102 has been diag-
nosed, don't forget to erase DTC U1120.

RED

RED-

WHITE

RED-

WHITE

RED-

WHITE

AK302832

B-10

B-17X

MFI 
RELAY

BATTERY

MASS AIRFLOW 
SENSOR

2

1

2

4

3

Mass Airflow Sensor Circuit

1

2

3

4

1

2

3 4

WHITE-GREEN

BLA

CK

POWERTRAIN CONTROL 
MODULE (PCM)

108

3

69

4

B-22

B-21

HEAT
SENSITIZING
RESISTANCE

100

99

92

91

93 94 95

96 97 98

101 102 103 104

105 106 107 108

109 110 111 112 113

52

51

53 54 55 56

57

58 59 60 61 62

63

64 65 66 67 68 69

70

71 72 73 74 75

76

77 78 79 80 81 82

83

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-52

.

CIRCUIT OPERATION

• The mass airflow sensor power is supplied from 

the MFI relay (terminal No. 4), and the ground is 
provided on the PCM (terminal No. 69).

• 5-volt power is applied to the mass airflow sensor 

output terminal (terminal No. 3) from the PCM 
(terminal No. 108).

.

TECHNICAL DESCRIPTION

• While the engine is running, the mass airflow 

sensor outputs voltage which corresponds to the 
mass airflow rate.

• The PCM checks whether the voltage output by 

the mass airflow sensor while the engine is run-
ning is within a specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Mass airflow sensor output voltage is out of specified 

range.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Not applicable

.

1

2

3

4

1

2

3

4

1

2

3

4

1

2

3

4

AK303014

CONNECTOR: B-17X

MFI RELAY

MFI RELAY

FRONT OF VEHICLE

B-17X

AB

AK303012

CONNECTOR: B-10

MASS AIRFLOW SENSOR

AB

B-10 (GR)

AK303013

CONNECTORS: B-21, B-22

PCM

AB

AIR CLEANER

B-22 (B)

B-21 (B)