Mitsubishi Galant (2004+). Manual - part 1349

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1089

INSPECTION PROCEDURE 32: A/C system.

.

COMMENT

• When the A/C is "ON" the PCM turns "ON" the 

power transistor in the PCM. The PCM delays 
A/C engagement momentarily while it increases 
idle r/min. Then the A/C compressor clutch relay 
coil will be energized. 
With this, the A/C compressor clutch relay turns 
"ON", and the A/C compressor clutch operates.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case: )

• Malfunction of the A/C control system.

• Improper connector contact, open circuit or 

short-circuited harness wire.

• Malfunction of the PCM.

GREEN

AK302882

81

POWERTRAIN CONTROL 
MODULE (PCM)

A/C COMPRESSOR CLUTCH
RELAY

A/C Circuit

B-21

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

AK303119

CONNECTOR: B-21

PCM

AB

AIR CLEANER

B-21

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1090

DIAGNOSIS

STEP 1. Check harness connector B-21 at PCM for 
damage.

Q: Is the harness connector in good condition?

YES : Go to Step 2.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

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)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1091

STEP 2. Check the circuit at PCM connector B-21.

(1) Disconnect the connectors B-21 and measure at the 

harness side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 81 and ground.

• Voltage should be battery positive voltage.

(4) Using a jumper wire, connect terminal No. 81 to ground.

• A/C compressor clutch relay should turn "ON".

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage and A/C compressor relay condition 

normal?
YES : Replace the PCM. Then confirm that the malfunction 

sympton is eliminated.

NO :  Refer to GROUP 55, Diagnosis 

− Introduction To 

Heater, Air Conditioning And Ventilation Diagnosis 

P.55A-5

. Then confirm that the malfunction symptom 

is eliminated.

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)

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

AK303276

B-21 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1092

DATA LIST REFERENCE TABLE

M1131152000940

CAUTION

• When shifting the selector lever to D range, the brakes should be applied so that the vehicle does 

not move forward.

• Driving tests always need two persons: one driver and one observer.

NOTE: Sensor 1 indicates the sensor mounted at a position closest to the engine, and sensor 2 indicates the 
sensor mounted at the position second close to the engine.
NOTE: Bank 1 indicates the right bank cylinder, and bank 2 indicates the left bank cylinder
NOTE: *

1

: In a new vehicle [driven approximately 500 km (311 mile) or less], the mass airflow sensor output 

value is sometimes 10% higher than the standard value.
NOTE: *

2

: The injector drive time represents the time when the cranking speed is at 250 r/min or below when 

the power supply voltage is 11 volts.
NOTE: *

3

: In a new vehicle [driven approximately 500 km (311 mile) or less], the injector drive time is some-

times 10% longer than the standard time.
NOTE: *

4

: Applicable to GST

NOTE: *

5

: Vehicles for Canada, the headlight, taillight, etc. remain lit even when the lighting switch is in "OFF" 

position but this is no problem for checks.

MUT-III SCAN 
TOOL DISPLAY

ITEM NO. 

INSPECTION ITEM

INSPECTION REQUIREMENT

NORMAL CONDITION

INSPECTION 
PROCEDURE NO.

REFERENCE 
PAGE

A/C 
RELAY

49

A/C 
compressor 
clutch relay

• Engine: warming up, idling

• A/C switch: "OFF"

OFF

Procedure 
No. 32

P.13B-1
089

• Engine: 

warming up, 
idling

• A/C switch: 

"ON"

A/C 
compressor 
clutch is not 
operating

OFF

A/C 
compressor 
clutch is 
operating

ON

APP SNS 
(MAIN)

78

Accelerator 
pedal position 
sensor (main)

Ignition switch: 
"ON"

Release the 
accelerator 
pedal

700 

− 1,300 

mV

Code No. 
P2122, 
P2123

P.13B-8
89

, 

P.13B-8
99

Depress the 
accelerator 
pedal gradually

Increases in 
response to 
the pedal 
depression 
stroke

Depress the 
accelerator 
pedal fully

4,000 mV or 
more