Mitsubishi Galant 9G. Manual — part 908

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-1074

.

AK303936

B-101 (GR)

B-102 (GR) B-117 (GR)

B-118 (GR)

AB

CONNECTORS: B-101, B-102, B-117, B-118

IGNITION COIL

AK303918AB

C-29

CONNECTOR: C-29

AK303059

CONNECTOR: B-23

PCM

AB

AIR CLEANER

B-23

AK303925AB

CONNECTOR: C-215

C-215

AK303923AB

CONNECTOR: C-308

C-308

AK303915AB

CONNECTOR: C-211

C-211

AK303872AB

A-13 (GR)

CONNECTOR: A-13

AK303937 AB

CONNECTOR: B-111

B-111 (B)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-1075

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

shorted harness wire.

• Malfunction of the PCM.

DIAGNOSIS

STEP 1. Check the ignition coil.
Refer to GROUP 16, Ignition System

− On-vehicle service −

Ignition Coil Check

P.16-38

.

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 connector B-101, B-102, B-117 and
B-118 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.

1

2

3

AK303919

B-101(GR)

B-102 (GR) B-117 (GR)

B-118 (GR)

CONNECTORS: B-101, B-102, B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-1076

STEP 3. Measure the power supply voltage at ignition coil
connectors B-101, B-102, B-117 and B-118.
(1) Disconnect the connector B-101, B-102, B-117 and B-118

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-101, B-102, B-117 and B-118 (terminal No. 1).

1

2

3

AK303919

B-101(GR)

B-102 (GR) B-117 (GR)

B-118 (GR)

CONNECTORS: B-101, B-102, B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK302146

1

2

3

B-101, B-102 , B-117 , B-118
HARNESS CONNECTORS:
COMPONENT SIDE

AD

AK303938

1

2

3

4

5

6

AB

CONNECTOR: C-308

C-308

HARNESS
CONNECTOR:
COMPONENT SIDE

1

2

3

AK303919

B-101(GR)

B-102 (GR) B-117 (GR)

B-118 (GR)

CONNECTORS: B-101, B-102, B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>

13A-1077

NOTE: Check harness after checking intermediate connectors
A-13, C-29, C-211, C-215 and C-308. If intermediate connec-
tors 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
connector B-101, B-102, B-117 and B-118.
(1) Disconnect the connectors B-101, B-102, B-117 and B-118

and measure at the harness side.

(2) Crank the engine.

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

• 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.

1

2

3

AK303919

B-101(GR)

B-102 (GR) B-117 (GR)

B-118 (GR)

CONNECTORS: B-101, B-102, B-117, B-118

HARNESS CONNECTOR:
COMPONENT SIDE

AB

AK302148

1

2

3

B-101, B-102, B-117, B-118
HARNESS CONNECTORS:
COMPONENT SIDE

AD