Mitsubishi Galant (2004+). Manual - part 1204

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-509

STEP 6. Check for harness damage between MFI relay 
connector B-17X (terminal No. 4) and No. 4 cylinder 
injector connector B-27 (terminal No. 1).

Q: Is the harness wire in good condition?

YES : Go to Step 7.
NO :  Repair it. Then go to Step 10.

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-510

STEP 7. Check harness connector B-23 at PCM for 
damage.

Q: Is the connector in good condition?

YES : Go to Step 8.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 10.

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-511

STEP 8. Check for open circuit and short circuit to ground 
and harness damage between No. 4 cylinder injector 
connector B-27 (terminal No. 2) and PCM connector B-23 
(terminal No. 139).

Q: Is the harness wire in good condition?

YES : Go to Step 9.
NO :  Repair it. Then go to Step 10.

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-512

STEP 9. Using the oscilloscope, check the No. 4 cylinder 
injector.

(1) Disconnect the No. 4 cylinder injector B-27 and connect the 

test harness special tool (MB991658) between the 
separated connectors. (All terminals should be connected)

(2) Connect the oscilloscope probe to the injector side 

connector terminal No. 2.
NOTE: When measuring with the PCM side connector, dis-
connect the all PCM connectors and connect check har-
ness special tool (MB991923) between the separated 
connectors. Then connect an oscilloscope probe to terminal 
No. 139.

(3) Start the engine and run at idle.

(4) Measure the waveform.

• The waveform should show a normal pattern similar to 

the illustration.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the waveform normal?

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 10.

STEP 10. 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 P0204 set?

YES : Repeat the troubleshooting.
NO :  The procedure is complete.

AK303110

M

1

2

CONNECTOR: B-27

B-27 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK102980

1 2

INJECTOR
CONNECTOR

MB991658

AC

OSCILLOSCOPE

AKX01557 AB

A

NORMAL  WAVEFORM

A:INJECTOR DRIVE TIME