Mitsubishi Outlander GS45X. Manual - part 1011

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-71

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.55A-7

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO :  Repair the CAN bus lines (Refer to GROUP 54C, 

precautions on how to repair the CAN bus lines 

P.54C-17

).

STEP 2. Using scan tool MB991958, read the diagnostic 
trouble code.
Check if an A/C-ECU DTC is set.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES : Refer to Diagnostic Trouble Code Chart 

P.55A-11

.

NO :  Go to Step 3.

STEP 3. Check A/C compressor assembly connector B-17 
for loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is A/C compressor assembly connector B-17 in good 

condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link 
connector

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-72

STEP 4. Check the A/C compressor clutch operation.
Connect the compressor connector terminal to the battery posi-
tive (+) terminal and ground the battery’s negative (-) terminal 
to the compressor unit. At that time, the A/C compressor clutch 
should make a definite operating sound.
Q: Can the sound (click) of the A/C compressor clutch 

operation be heard?
YES : Go to Step 5.
NO :  Replace the compressor magnet clutch. 

STEP 5. Check A/C compressor clutch relay connector 
B-16X for loose, corroded or damaged terminals, or 
terminals pushed back in the connector.
Q: Is A/C compressor clutch relay connector B-16X in good 

condition?
YES : Go to Step 6.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.

AC711346

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-73

STEP 6. Check the A/C compressor clutch relay continuity.

Follow the table below to check the A/C compressor clutch 
relay for continuity.

Q: Is the A/C compressor clutch relay in good condition?

YES : Go to Step 7.
NO :  Replace the A/C compressor clutch relay. 

Battery voltage

Tester 
connection

Specified 
condition

Not applied

3 

− 4

Open circuit

• Connect terminal 2 

to the positive 
battery terminal

• Connect terminal 1 

to the negative 
battery terminal

3 

− 4

Less than 2 ohms

AC803381

AB

A/C compressor clutch relay

<2.4 L>

4

1

2

3

3

1

4

2

AC702637

4

1

2

3

3

1

4

2

AC

A/C compressor clutch relay

<3.0 L>

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-74

STEP 7. Check engine control module connector B-11 for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is engine control module connector B-11 in good 

condition?
YES : Go to Step 8.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

.

STEP 8. Measure the voltage at A/C compressor assembly 
connector B-17. 
(1) Disconnect A/C compressor assembly connector B-17 and 

measure the voltage at the wiring harness side.

(2) Disconnect powertrain control module connector B-11 and 

ground harness side terminal No.102.

(3) Turn the ignition switch to the "ON" position.
(4) A/C compressor assembly connector B-17 terminal 1 and 

ground.

• The measured value should be approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts?

YES :  Go to Step 13.
NO :   Go to Step 9.

STEP 9. Measure the voltage at A/C compressor clutch 
relay connector B-16X. 
(1) Disconnect A/C compressor connector B-16X and measure 

the voltage at the relay box side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 4 and ground.

• The measured value should be approximately 12 volts 

(battery positive voltage).

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

• The measured value should be approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts?

YES :  Go to Step 11.
NO :   Go to Step 10.

AC608254 BV

Harness side: B-17

AC608254 BW

Harness side: B-16X