Mitsubishi Galant (2004+). Manual - part 1277

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-801

STEP 2. Measure the power supply voltage at power 
steering pressure switch connector B-31 by backprobing. 

(1) Do not disconnect the connector B-31. 
(2) Start the engine and run at idle. 

(3) Measure the voltage between terminal No. 1 and ground by 

backprobing. 

• When steering wheel is not turned, voltage should be 

battery positive voltage. 

• When steering wheel is turned, voltage should be 1 volt 

or less. 

(4) Turn the ignition switch to the "LOCK" (OFF) position. 
Q: Is the measured voltage within the specified range? 

YES : Go to Step 3. 
NO :  Go to Step 5. 

STEP 3. Check harness connector B-31 at power steering 
pressure switch for damage. 

Q: Is the harness connector in good condition? 

YES : Go to Step 4. 
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14. 

AK303162

1

AB

POWER STEERING
PRESSURE SWITCH

B-31 (B)

CONNECTOR: B-31

HARNESS
CONNECTOR:
COMPONENT SIDE

1

AK303163

B-31 HARNESS 
CONNECTOR: 
HARNESS SIDE

AB

AK303162

1

AB

POWER STEERING
PRESSURE SWITCH

B-31 (B)

CONNECTOR: B-31

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-802

STEP 4. Using scan tool MB991958, check data list item 27: 
Power Steering Pressure Switch. 

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. 
(1) Connect scan tool MB991958 to the data link connector. 
(2) Start the engine and run at idle. 
(3) Set scan tool MB991958 to the data reading mode for item 

27, Power Steering Pressure Switch. 

• If the steering wheel is not turned while idling, "OFF" will 

be displayed. 

• If the steering wheel is turned while idling, "ON" will be 

displayed. 

(4) Turn the ignition switch to the "LOCK" (OFF) position. 
Q: Is the switch operating properly? 

YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

P.00-6

.

NO :  Replace the PCM. Then go to Step 14. 

STEP 5. Check harness connector B-31 at power steering 
pressure switch for damage. 

Q: Is the harness connector in good condition? 

YES : Go to Step 6. 
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 14.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AK303162

1

AB

POWER STEERING
PRESSURE SWITCH

B-31 (B)

CONNECTOR: B-31

HARNESS
CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-803

STEP 6. Measure the power supply voltage at power 
steering pressure switch harness side connector B-31. 

(1) Disconnect the connector B-31 and measure at the harness 

side. 

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

(3) Measure the voltage between terminal No. 1 and ground. 

• Voltage should be battery positive voltage. 

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

present?
YES : Go to Step 11. 
NO :  Go to Step 7. 

AK303162

1

AB

POWER STEERING
PRESSURE SWITCH

B-31 (B)

CONNECTOR: B-31

HARNESS
CONNECTOR:
COMPONENT SIDE

1

AK303163

B-31 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AC

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-804

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