Mitsubishi Galant (2004+). Manual - part 1347

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1081

CIRCUIT OPERATION

• The ignition coil is energized by battery positive 

voltage from the ignition switch.

• When the PCM turns off its internal power tran-

sistor, battery positive voltage is applied to the 
ignition power transistor (terminal No. 3) inside 
the ignition coil, causing the ignition power tran-
sistor to be turned on.

• If the ignition power transistor is turned on, the 

primary circuit of the ignition coil is energized by 
grounding the ignition coil through terminal No. 2, 
causing the primary current to flow to the ignition 
coil.

.

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

• Malfunction of the ignition coil.

• Malfunction of the ignition power transistor.

• Improper connector contact, open circuit or 

short-circuit harness wire.

• Malfunction of the PCM.

DIAGNOSIS

STEP 1. Check the ignition coil.
(1) Remove the intake manifold.
(2) Refer to GROUP 16, Ignition System 

− On-vehicle service − 

Ignition Coil Check 

P.16-37

.

Q: Are there any abnormalities?

YES : Replace the ignition coil. Then confirm that the 

malfunction symptom is eliminated. 

NO :  Go to Step 2.

STEP 2. Check harness connectors B-114, B-117, B-118, 
B-102, B-103, B-101 at ignition coil for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

AK303233

1

2

3

AB

B-118 (GR)

B-102 (GR)

B-101 (GR)

B-117 (GR)

B-103 (GR)

B-114 (GR)

CONNECTOR: B-101, B-102, B-103, B-114,
                         B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1082

STEP 3. Measure the power supply voltage at ignition coil 
connectors B-114, B-117, B-118, B-102, B-103, B-101.

(1) Disconnect the connector B-114, B-117, B-118, B-102, 

B-103, B-101 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 5.
NO :  Go to Step 4.

STEP 4. Check for open circuit between ignition switch 
connector C-308 (terminal No. 2) and ignition coil 

connectors B-114, B-117, B-118, B-102, B-103, B-101 
(terminal No. 1).

AK303233

1

2

3

AB

B-118 (GR)

B-102 (GR)

B-101 (GR)

B-117 (GR)

B-103 (GR)

B-114 (GR)

CONNECTOR: B-101, B-102, B-103, B-114,
                         B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

1

2

3

AK303273

B-101, B-102, B-103, B-114, 
B-117, B-118 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

1

2

3

4

5

6

AK203282

CONNECTOR: C-308

C-308

HARNESS
CONNECTOR:
COMPONENT SIDE

AB

AK303233

1

2

3

AB

B-118 (GR)

B-102 (GR)

B-101 (GR)

B-117 (GR)

B-103 (GR)

B-114 (GR)

CONNECTOR: B-101, B-102, B-103, B-114,
                         B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1083

NOTE: Check harness after checking intermediate connectors 
A-13, B-32, C-29, C-211, C-215 and C-308. If intermediate con-
nectors are damaged, repair or replace them. Refer to GROUP 
00E, Harness Connector Inspection 

P.00E-2

. Then confirm that 

the malfunction symptom is eliminated.
Q: Is the harness wire in good condition?

YES : Repair harness wire between ignition switch 

connector C-308 (terminal No. 2) and capacitor 
connector B-111 (terminal No. 1) because of short 
circuit to ground. Then confirm that the malfunction 
symptom is eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

STEP 5. Check the circuit at ignition coil harness side 
connectors B-114, B-117, B-118, B-102, B-103, B-101.

(1) Disconnect the connectors B-114, B-117, B-118, B-102, 

B-103, B-101 and measure at the harness side.

(2) Crank the engine.

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

NOTE: The average voltage through an analog voltmeter is 
described in this service manual (because the average volt-
age is too stable to be shown on a digital voltmeter).

• Voltage should be 0.3 and 3.0 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 0.3 and 3.0 volts?

YES : Go to Step 8.
NO :  Go to Step 6.

AK303233

1

2

3

AB

B-118 (GR)

B-102 (GR)

B-101 (GR)

B-117 (GR)

B-103 (GR)

B-114 (GR)

CONNECTOR: B-101, B-102, B-103, B-114,
                         B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

1

2

3

AK303275

B-101, B-102, B-103, B-114, 
B-117, B-118 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1084

STEP 6. Check connector B-23 at PCM for damage.

Q: Is the connector in good condition?

YES : Go to Step 7.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

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