Mitsubishi Galant. Manual — part 180

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-401

STEP 9. Check connector C-39 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 10.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then confirm that the

malfunction symptom is eliminated.

STEP 10. Check for open circuit between ignition coil
connector and PCM connector.

a. Check the harness wire between ignition coil connector B-

09 terminal 3 and PCM connector C-39 terminal 11 when
checking ignition coil 1.

b. Check the harness wire between ignition coil connector B-

23 terminal 3 and PCM connector C-39 terminal 12 when
checking ignition coil 2.

Q: Is the harness wire in good condition?

YES : Replace the PCM. Then confirm that the malfunction

symptom is eliminated.

NO : Repair it. Then confirm that the malfunction symptom

is eliminated.

AK000280

CONNECTOR : C-39

PCM

AW

AK000639AB

B-23

B-09

CONNECTORS:B-09,B-23

AK000280

CONNECTOR : C-39

PCM

AW

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-402

STEP 11. Using the oscilloscope, check the ignition failure
sensor.
(1) Disconnect the ignition failure sensor connector B-01, and

connect test harness special tool (MB991658) in between.
(All terminals should be connected.)

(2) Connect the oscilloscope probe to the ignition failure sensor

side connector terminal 2.

(3) Start the engine and run at idle.
(4) Check the waveform.

•

The waveform should show a 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.00-8

).

NO : Go to Step 12.

STEP 12. Check the circuit at ignition failure sensor
harness side connector B-01.
(1) Disconnect the connectors B-01 and measure at the

harness side.

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

•

Voltage should be 4 volts or more.

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

Q: Is the voltage normal?

YES : Repair harness wire between ignition failure sensor

connector B-01 terminal 1 and ground because of
open circuit or harness damage. Then confirm that
the malfunction symptom is eliminated.

NO : Go to Step 13.

STEP 13. Check connector C-40 at PCM for damage.
Q: Is the connector in good condition?

YES : Go to Step 14.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection(

P.00E-2

). Then confirm that the

malfunction symptom is eliminated.

AK000416 AB

OSCILLOSCOPE
PROBE

IGNITION FAILURE
SENSOR CONNECTOR

OSCILLOSCOPE

1 2 3 4

AK000417

NORMAL WAVEFORM (AT IDLING)

NOTE : CYCLE (T) SHORTENS AS
THE ENGINE SPEED RISES.

AK000417AB

10V

T

AK000418

4 3 2 1

B-01 HARNESS
SIDE CONNECTOR

AC

AK000280

CONNECTOR : C-40

PCM

AV

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-403

STEP 14. Check for open circuit between ignition failure
sensor connector B-01 terminal 2 and PCM connector C-40
terminal 43.
Q: Is the harness wire in good condition?

YES : Replace the PCM. Then confirm that the malfunction

symptom is eliminated.

NO : Repair it. Then confirm that the malfunction symptom

is eliminated.

INSPECTION PROCEDURE 33: A/C system.

ACX02471

CONNECTOR:B-01

IGNITION
FAILURE
SENSOR

AH

AK000280

CONNECTOR : C-40

PCM

AV

AK000486

GREEN-

RED

GREEN

POWERTRAIN CONTROL
MODULE(PCM)

83

20

C-39
(MU803784)

C-41
(MU803782)

A/C COMPRESSOR
RELAY

AUTOMATIC
COMPRESSOR
CONTROLLER

12

11

16

5 6

7 8

21

13
27

14
28

15
29

17
30

18
31

19
32

20
33

22
34

23
35

1

24

3

26

9

2

25

10

4

98

78

71

88 89

76 77

72
79
91

73
80

74

75

81
92

8283
93

8485

94

8687

9596

90

97

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-404

COMMENT

•

When the A/C is "ON," the battery positive
voltage is applied on the PCM (terminal 83) from
the automatic compressor controller.
When battery positive voltage is applied to the
PCM, the PCM turns "ON" the power transistor in
the PCM. The PCM delays A/C engagement
momentarily while it increases idle rpm. Then the
A/C compressor clutch relay coil will be
energized.

With this, the A/C compressor clutch relay turns
"ON," and the A/C compressor clutch functions.

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

•

Malfunction of the A/C control system.

•

Malfunction of the A/C switch.

•

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

•

Malfunction of the PCM.

DIAGNOSIS

STEP 1. Check connector C-39, C-41 at PCM 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.

STEP 2. Check the circuit at PCM connector C-39.
(1) Disconnect the connectors C-39 and measure at the

harness side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 20 and ground.

•

Voltage should be battery positive voltage.

(4) Using a jumper wire, connect terminal 20 to ground.

•

A/C compressor relay should turn "ON".

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

Q: Is the voltage and A/C compressor relay condition

normal?
YES : Go to Step 3.
NO : Refer to GROUP 55, Heating and air conditioning

−

Introduction To Heater, Air Conditioning And
Ventilation Diagnosis (

P.55-4

). Then confirm that the

malfunction symptom is eliminated.

AK000280

CONNECTORS : C-39, C-41

C-39

C-41

PCM

AZ

AK000280

CONNECTORS : C-39, C-41

C-39

C-41

PCM

AZ

AKX01448

C-39 HARNESS
SIDE CONNECTOR

8 7

6 5

4 3

2

1
9

10

11

12

13

14

15

16

17

18

19

20

21

22

23
3534

3332 3130

29282726

25 24

AE