Mitsubishi Galant (2004+). Manual - part 986

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-761

STEP 7. Measure the power supply voltage at PCM 
connector B-21 by using power plant ECU check harness 
special tool MB991923. 

(1) Disconnect the all PCM connectors and connect power 

plant ECU check harness special tool MB991923 between 
the separated connectors. 

(2) Disconnect the power steering pressure switch connector 

B-31. 

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

AK303018

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CONNECTOR: B-21

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER

B-21 (B)

AK202989

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AB

POWER PLANT ECU 
CHECK HARNESS CONNECTOR

MB991923

PCM

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-762

(4) Measure the voltage between terminal No. 78 and ground. 

• Voltage should be between battery positive voltage. 

(5) Turn the ignition switch to the "LOCK" (OFF) position. 
Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 8. 
NO :  Go to Step 9.

STEP 8. Check harness connector B-21 at PCM for 
damage. 

Q: Is the harness connector in good condition? 

YES : Repair harness wire between power steering 

pressure switch connector B-31 (terminal No. 1) and 
PCM connector B-21 (terminal No. 78) because of 
open circuit. Then go to Step 14.

NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14.

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AK202990AB

POWER PLANT ECU 
CHECK HARNESS 
CONNECTOR 

AK303018

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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) <2.4L ENGINE>

13A-763

STEP 9. Check harness connector B-21 at PCM for 
damage. 

Q: Is the harness connector in good condition? 

YES : Go to Step 10. 
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14.

AK303018

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56

54 53 52 51

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62 61 60 59 58

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69 68 67 66 65 64

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75 74 73 72 71

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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) <2.4L ENGINE>

13A-764

STEP 10. Check for short circuit to ground between power 
steering pressure switch connector B-31 (terminal No. 1) 
and PCM connector B-21 (terminal No. 78). 

Q: Is the harness wire in good condition? 

YES : Replace the PCM. Then go to Step 14.
NO :  Repair it. Then go to Step 14.

STEP 11. Replace the power steering pressure switch. 

(1) Replace the power steering pressure switch. 
(2) Check the trouble symptoms. 

(3) Read in the diagnostic trouble code (DTC). 
Q: Is DTC P0551 set?

YES : Go to Step 12. 
NO :  Go to Step 14.

AK303881

1

AB

CONNECTOR: B-31

B-31 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE

AK303018

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82 81 80 79 78 77

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CONNECTOR: B-21

PCM

AB

HARNESS CONNECTOR: 
COMPONENT SIDE

AIR CLEANER

B-21 (B)

AK303881

1

AB

CONNECTOR: B-31

B-31 (B)

HARNESS 
CONNECTOR:
COMPONENT SIDE