Mitsubishi Lancer Evolution IX. Manual — part 466

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-339

STEP 22. Connector check: C-121 engine-ECU
connector.

Q: Is the check result normal?

YES :

Check intermediate connectors A-29*

1

or

C-31*

2

, and repair if necessary. If

intermediate connectors are normal, check
and repair harness between A-07X (terminal
No. 3) condenser fan relay (high) connector
and C-121 (terminal No. 30) engine-ECU
connector.

• Check power supply for open circuit

and damage.

NO :

Repair or replace the connector.

STEP 23. Perform voltage measurement at A-34
condenser fan motor connector.

• Disconnect connector, and measure at harness

side.

• Disconnect C-121 engine-ECU connector, and

earth terminal No. 30.

• Ignition switch: "ON"

AK501995

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30

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26

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29

31

32

33

34

35

1

10

AB

Connector: C-121

C-121 (GR)

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

AK305267

2

1

3

4

A-07X

Connector: A-07X

AB

Harness side
connector

Relay box’s
triangle marks

AK305266

1

2

A-34(B)

AB

Harness side
connector

Connector: A-34

AK305267

2

1

3

4

A-07X

Connector: A-07X

AB

Harness side
connector

Relay box’s
triangle marks

AK501995

2

3

4

5

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11

12

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30

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29

31

32

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34

35

1

10

AB

Connector: C-121

C-121 (GR)

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-340

• Voltage between terminal No. 2 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 24 .

NO :

Check intermediate connectors A-29*

1

or

C-31*

2

, and repair if necessary. If

intermediate connectors are normal, check
and repair harness between A-07X (terminal
No. 3) condenser fan relay (high) connector
and C-121 (terminal No. 30) engine-ECU
connector.

• Check power supply for open circuit

and damage.

STEP 24. Connector check: A-34 condenser fan
motor connector.

Q: Is the check result normal?

YES :

Go to Step 25 .

NO :

Repair or replace the connector.

STEP 25. Check harness between A-07X
(terminal No. 3) condenser fan relay (high)
connector and C-121 (terminal No. 30)
engine-ECU connector.

NOTE: Before checking harness, check intermediate
connector A-29*

1

or C-31*

2

, and repair if necessary.

• Check output line for damage.

Q: Is the check result normal?

YES :

Go to Step 26 .

NO :

Repair the damaged harness wire.

AK305266

1

2

A-34(B)

AB

Harness side
connector

Connector: A-34

AK305267

2

1

3

4

A-07X

Connector: A-07X

AB

Harness side
connector

Relay box’s
triangle marks

AK501995

2

3

4

5

6

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8

9

11

12

13

14

15

16

17

18

19

20

30

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22

23

24

25

26

27

28

29

31

32

33

34

35

1

10

AB

Connector: C-121

C-121 (GR)

C-121 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-341

STEP 26. Connector check: A-35 condenser fan
motor connector.

Q: Is the check result normal?

YES :

Go to Step 27 .

NO :

Repair or replace the connector.

STEP 27. Perform resistance measurement at
A-35 condenser fan motor connector.

• Disconnect connector, and measure at harness

side.

• Resistance between terminal No. 2 and earth.

OK: 2

Ω or less

Q: Is the check result normal?

YES :

Replace the engine-ECU.

NO :

Repair the damaged harness wire.

Inspection Procedure 27: A/C Switch System

AK305443

1

2

A-35(GR)

AB

Harness side
connector

Connector: A-35

AK305443

1

2

A-35(GR)

AB

Harness side
connector

Connector: A-35

AK501832

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92

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83

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96

100

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78

71

90

76 77

75

72
79

P

Engine-ECU

83

A/C-ECU

A/C Switch circuit

C-117

(MU803783)

AB

Wire colour code
B: Black LG: Light green G: Green L: Blue W: White Y: Yellow SB: Sky blue BR: Brown O: Orange GR: Gray
R: Red P: Pink V: Violet PU: Purple

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI)

13A-342

OPERATION

• The battery voltage is applied to the engine-ECU

(terminal No. 83) from the A/C-ECU (terminal No.
1).

FUNCTION

• When the A/C switch is in "ON" position, A/C

switch ON signal is inputted to the engine-ECU
from the A/C-ECU. In response to the signal, the
engine-ECU controls the A/C compressor relay.

PROBABLE CAUSES

• Failed A/C

• Failed A/C system

• Open/short circuit in A/C circuit or loose connec-

tor contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Perform voltage measurement at C-117
engine-ECU connector.

• Measure engine-ECU terminal voltage.

• Engine: Idling

• A/C set temperature:

Maximum Cool when temperature in cabin is

25

°C or more

Maximum Hot when temperature in cabin is 25

°C

or less

• Voltage between terminal No. 83 and earth.

OK:

System voltage (when A/C is ON)
0.5 V or less (when A/C is OFF)

Q: Is the check result normal?

YES :

Go to Step 2 .

NO :

Check A/C system (Refer to GROUP 55

−

Troubleshooting

− Check Chart for Trouble

Symptoms

P.55-29

)

AK501996

80

87

81

94

85

82

84

93

86

98

99

74

92

73

83

88

91

95

97 96

100

89

78

71

90

76

77

75

72
79

AB

Connector: C-117

C-117 (GR)

C-117 (GR)

Harness side connector

<L. H. drive vehicles>

<R. H. drive vehicles>