Mitsubishi Galant (2004+). Manual — part 1340

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1053

STEP 2. Check the MFI relay.

CAUTION

Because it is not possible to distinguish the top and the
bottom of the MFI relay, inspect it with the triangle mark
printed on the relay facing upward.
(1) Remove the MFI relay.

(2) Check for continuity between the MFI relay terminals No. 2

and No. 3.

• There should be continuity. (approximately 70 ohms)

(3) Use jumper wires to connect MFI relay terminal No. 2 to the

positive battery terminal and terminal No. 3 to the negative
battery terminal.

(4) Check for continuity between the MFI relay terminals No. 1

and No. 4 while connecting and disconnecting the jumper
wire at the negative battery terminal.

• Should be less than 2 ohms. (Negative battery terminal

connected)

• Should be open loop. (Negative battery terminal discon-

nected)

(5) Install the MFI relay.
Q: Is the measured resistance within the specified range?

YES : Go to Step 3.
NO : Replace the MFI relay. Then confirm that the

malfunction symptom is eliminated.

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

AK204164

1

2

3

4

MFI RERAY
SIDE
CONNECTOR

AB

1

2

3

4

AK203257

MFI RELAY SIDE
CONNECTOR

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1054

STEP 3. Measure the power supply voltage at MFI relay
harness side connector B-17X.

CAUTION

Because it is difficult to distinguish the top and bottom of
the MFI relay connector at the wiring harness, inspect it by
using triangle mark on the junction block as reference.
(1) Disconnect the connector B-17X and measure at the

harness side.

(2) Measure the voltage between terminals No. 1, No. 2 and

ground.

• Voltage should be battery positive voltage.

Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 4.
NO : Check harness connector A-13 at intermediate

connector for damage, and repair or replace as
required. Refer to, GROUP 00E, Harness Connector
Inspection

P.00E-2

. If intermediate connector is in

good condition, repair harness wire between relay
box (9) and MFI relay connector B-17X (terminals No.
1, No. 2) because of open circuit. Then confirm that
the malfunction symptom is eliminated.

1

2

3

4

AK303017

CONNECTOR: B-17X

FRONT OF VEHICLE

B-17X

AB

HARNESS
CONNECTOR:
COMPONENT SIDE

RELAY BOX

2

1

3

4

AK303247

B-17X HARNESS
CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1055

STEP 4. Check harness connector B-20 and B-21 at PCM
for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 5.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then confirm that the

malfunction symptom is eliminated.

AK303248

25

21

24 23 22

29 28 27 26

34 33 32 31 30

38 37 36 35

43 42 41 40 39

55

56

54 53 52 51

57

62 61 60 59 58

63

69 68 67 66 65 64

70

75 74 73 72 71

76

82 81 80 79 78 77

83

CONNECTORS: B-20, 21

PCM

AIR CLEANER

B-20

B-21 (B)

AB

B-20 HARNESS CONNECTOR:
COMPONENT SIDE

B-21 HARNESS CONNECTOR:
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1056

STEP 5. Measure the ignition switch-IG signal voltage at
PCM harness side connector B-20.

(1) Disconnect the connector B-20 and measure at the harness

side.

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

(3) Measure the voltage between terminal No. 43 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 6.
NO : Check harness connector C-214 and C-215 at

intermediate connector for damage, and repair or
replace as required. Refer to, GROUP 00E, Harness
Connector Inspection

P.00E-2

. If intermediate

connectors are in good condition, repair harness wire
between ignition switch connector C-308 (terminal
No. 2) and PCM connector B-21 (terminal No. 43)
because of open circuit. Then confirm that the
malfunction symptom is eliminated.

AK303092

25

21

24 23 22

29 28 27 26

34 33 32 31 30

38 37 36 35

43 42 41 40 39

CONNECTOR: B-20

B-20

PCM

AB

HARNESS CONNECTOR:
COMPONENT SIDE

AIR CLEANER

25

21

24 23 22

29 28 27 26

34 33 32 31 30

38 37 36 35

43 42 41 40 39

AK303249

B-20 HARNESS
CONNECTOR:
COMPONENT SIDE

AB