Mitsubishi Lancer Evolution X. Manual - part 437

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-813

Inspection procedure 27: A/C system

AK900375

71 72 73 74 75 76 77 78 79 80 81 82

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109

108

107

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115 116

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105

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117

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1

10

1

WHITE

WHITE

7

10A

ORANGE

A/C COMPRESSOR
CLUTCH RELAY

4

2

1

A-13X

B-14

MU802655

A-54

OFF

A/C
REFRIGERANT
TEMPERATURE
SWITCH 

A/C COMPRESSOR CLUTCH ASSEMBLY

A/C
COMPRESSOR
CLUTCH

A/C COMPRESSOR CLUTCH RELAY CIRCUIT

102

AB

B-109

LIGHT

GREEN

LIGHT

GREEN

3

1

5

OFF

ON

ON

FUSIBLE LINK  36

ON

→

OFF

: 155˚C
OFF

→

ON

: 125˚C

RELAY BOX
(ENGINE COMPARTMENT)

ENGINE CONTROL MODULE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-814

.

CIRCUIT OPERATION

• When the A/C switch ON signal is input into the 

ECM, the ECM turns ON the A/C compressor 
relay. This causes battery positive voltage to be 
supplied to the A/C compressor and the magnet 
clutch actuates.

.

COMMENT

• When the A/C is "ON" the ECM turns "ON" the 

power transistor in the ECM. The ECM delays 
A/C engagement momentarily while it increases 
idle speed. 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 operates.

.

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

• Malfunction of the A/C control system.
• Open or shorted A/C compressor relay circuit, 

harness damage, or connector damage.

• Malfunction of the ECM.

DIAGNOSIS

STEP 1. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness 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.

AK704229AB

Connector: A-13

A-13

AK704605

Connector: A-17X

A/C compressor
clutch relay

A-17X

AB

AK704235 AB

Connector: B-10

ECM

B-10 (GR)

AK704604

Connector: B-110

B-110 (B)

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-815

STEP 2. Check the circuit at ECM connector B-10.
(1) Disconnect the connectors B-10 and measure at the 

harness side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 102 and ground.

• Voltage should be battery positive voltage.

(4) Using a jumper wire, connect terminal No. 102 to ground.

• A/C compressor clutch 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 : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, Diagnosis 
− ID Code Registration Judgment Table <Vehicles with 

KOS> 

P.42B-14

 or GROUP 42C, Diagnosis − ID 

Codes Registration Judgment Table <Vehicles with 
WCM> 

P.42C-10

. Then confirm that the malfunction 

symptom is eliminated.

NO  :  Refer to GROUP 55, Automatic A/C Diagnosis − 

Diagnostic Trouble Code Chart 

P.55-10

. Then confirm 

that the malfunction symptom is eliminated.

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94 93 92 91 90 89 88 87 86 85 84 83

99 98 97 96 95

100

101

102

103

104

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106

112

113

114

109 108

107

110

111

115

116

117

118

AK700226AC

B-10 harness
connector:
component side 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-816

Inspection procedure 28: Engine oil pressure switch system

.

CIRCUIT OPERATION

• Battery voltage is applied to the oil pressure 

switch (terminal No. 1) from the engine-ECU (ter-
minal No. 36).

.

COMMENT

• Detect the engine oil pressure conditions and 

enter the result into the ECM. After starting the 
engine if the oil pressure rises to higher than the 
given pressure, the engine oil pressure switch 
turns OFF. Under this condition the ECM sends 
the command of turning off the oil warning lamp 
to the combination meter via CAN.

.

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

• Engine oil pressure switch failed.
• Open or shorted engine oil pressure switch cir-

cuit, harness damage, or connector damage.

• ECM failed.

AK704606

1

2

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1

36

GRA

Y

ENGINE OIL
PRESSURE
SWITCH

B-15

1

ENGINE OIL PRESSURE SWITCH CIRCUIT

AB

B-09

OFF

ON

ENGINE
CONTROL
MODULE

AK704227

Connector: B-09

ECM

B-09 (GR)

AB

AK704607AB

B-15

Connector: B-15

Throttle
body

Engine oil
pressure switch