Mitsubishi Galant. Manual — part 175

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-381

•

A battery positive voltage is constantly supplied
to the PCM (terminal 66) as the backup power.

•

The PCM (terminals 42, 48) is grounded to the
vehicle body.

TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:）

））

）

•

Malfunction of the ignition switch.

•

Malfunction of the MFI relay.

•

Improper connector contact, open circuit or short-
circuited harness wire.

•

Disconnected PCM ground wire.

•

Malfunction of the PCM.

DIAGNOSIS

STEP 1. Check connector A-21X at MFI relay for damage.
Q: Is the connector in good condition?

YES : Go to Step 2.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then confirm that the

malfunction symptom is eliminated.

AK000555AB

CONNECTOR : A-21X

MFI RELAY

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-382

STEP 2. Check the MFI relay
(1) Remove the MFI relay.
(2) Check for continuity between the MFI relay terminals 2 and

4.

•

There should be continuity (approximately 70

Ω

)

(3) Use jumper wires to connect MFI relay terminal 4 to the

positive battery terminal and terminal 2 to the negative
battery terminal.

(4) Check the continuity between the MFI relay terminals 1 and

3 while connecting and disconnecting the jumper wire at
the negative battery terminal.

•

Should be less than 2 ohm.(Negative battery terminal
connected)

•

Should be open loop.(Negative battery terminal
disconnected)

(5) Install the MFI relay.

Q: Is the voltage normal?

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

malfunction symptom is eliminated.

STEP 3. Check the power supply voltage at MFI relay
harness side connector A-21X.
(1) Disconnect the connector A-21X and measure at the

harness side.

(2) Measure the voltage between terminal 3, 4 and ground.

•

Voltage should be battery positive voltage.

Q: Is the voltage normal?

YES : Go to Step 4.
NO : Check harness connector C-04 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 fusible
link (13) and MFI relay connector A-21X terminal 3, 4
because of open circuit. Then confirm that the
malfunction symptom is eliminated.

AK000555AB

CONNECTOR : A-21X

MFI RELAY

AK000369AB

MFI RELAY SIDE
CONNECTOR

1 2
3 4

AK000370AB

MFI RELAY SIDE
CONNECTOR

1 2
3 4

AK000371AB

1

2

3

4

A-21X HARNESS
SIDE CONNECTOR

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-383

STEP 4. Check connector C-40 and C-41 at PCM for
damage.
Q: Is the 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.

STEP 5. Check the ignition switch-IG signal voltage at PCM
harness side connector C-41.
(1) Disconnect the connector C-41 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 98 and ground.

•

Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES : Go to Step 6.
NO : Check harness connector C-04, C-66 and C-73 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-58 terminal 2
and PCM connector C-41 terminal 98 because of
open circuit. Then confirm that the malfunction
symptom is eliminated.

STEP 6. Check the backup power supply voltage at PCM
harness side connector C-40.
(1) Disconnect the connector C-40 and measure at the harness

side.

(2) Measure the voltage between terminal 66 and ground.

•

Voltage should be battery positive voltage.

Q: Is the voltage normal?

YES : Go to Step 7.
NO : Check harness connector C-17 and C-66 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 fusible link (4) and PCM connector C-40
terminal 66 because of open circuit. Then confirm that
the malfunction symptom is eliminated.

AK000280

CONNECTORS : C-40, C-41

C-41

C-40

PCM

AX

AKX01435

71

72

73

74

75

76

77
89 88 87 86 858483 82 8180 7978

90

91

92

93

94

95

96

97

98

C-41 HARNESS
SIDE CONNECTOR

AD

AKX01436

41

42

43

44

45

46
57 56 55 54 53 52

48 47

58

59

60

61

62

66 65 64

63

51 50 49

C-40 HARNESS
SIDE CONNECTOR

AD

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-384

STEP 7. Check the continuity at PCM harness side
connector C-40.
(1) Disconnect the connector C-40 and measure at the harness

side.

(2) Check for the continuity between terminal (42, 48) and

ground.

•

Should be less than 2 ohm.

Q: Is the continuity normal?

YES : Go to Step 8.
NO : Repair harness wire between PCM connector C-40

terminal (42, 48) and ground because of open circuit.
Then confirm that the malfunction symptom is
eliminated.

STEP 8. Check the power supply voltage at PCM harness
side connector C-40.
(1) Disconnect the connector C-40 and measure at the harness

side.

(2) Measure the voltage between terminal 49 and ground.

•

Voltage should be battery positive voltage.

Q: Is the voltage normal?

YES : Go to Step 9.
NO : Repair harness wire between MFI relay connector A-

21X terminal 2 and PCM connector C-40 terminal 49
because of open circuit. Then confirm that the
malfunction symptom is eliminated.

STEP 9. Check the power supply voltage at PCM harness
side connector C-40.
(1) Disconnect the connector C-40 and measure at the harness

side.

(2) Using a jumper wire, connect terminal 49 to ground.
(3) Measure the voltage between terminal (41, 47) and ground.

•

Voltage should be battery positive voltage.

Q: Is the voltage normal?

YES : Replace the PCM. Then confirm that the malfunction

symptom is eliminated.

NO : Repair harness wire between MFI relay connector A-

21X terminal 1 and PCM connector C-40 terminal (41,
47) because of open circuit. Then confirm that the
malfunction symptom is eliminated.

AKX01437

46 45 44

43 42 41

47

48

49

50

51

52

53

54

55

56

57
66 65 64

63 62 6160

59 58

C-40 HARNESS
SIDE CONNECTOR

AE

AK000406

46 4544

43 42 41

47

48

49

50

51

52

53

54

55

56
66 6564

6362 6160

59 58

C-40 HARNESS
SIDE CONNECTOR

AC

AKX01438

46 45 44

43 42 41

47

48

49

50

51

52

53

54

55

56

57
66 65 64

63 62 6160

59 58

C-40 HARNESS
SIDE CONNECTOR

AE