Mitsubishi Montero (2002-2004). Manual - part 755

TSB Revision

SYMPTOM PROCEDURES

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INSPECTION PROCEDURE 24: Purge Flow Test of the Evaporative Emission Canister Failure.

.

COMMENT

• The test fails when the purge line or purge port is 

clogged or if the evaporative emission purge 
solenoid fails.

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

• Purge line or purge port is clogged.

• Malfunction of the evaporative emission purge 

solenoid.

• Evaporative emission canister is clogged.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC set?

YES : Refer to GROUP 13A, Diagnostic Trouble Code Chart 

P.13Ab-22

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NO :  Refer to GROUP 17, Emission Control System 

− 

Purge Control System Check (Purge Flow Check) 

P.17-61

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INSPECTION PROCEDURE 25: Pressure Test of the Evaporative System Failure

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COMMENT

• The test fails if there is a leak from the fuel tank or 

vapor line.

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

• Loose fuel tank filler tube cap.

• Broken seal in fuel tank, vapor line evaporative 

emission canister.

DIAGNOSIS

STEP 1. Check the evaporative emission purge solenoid.
Refer to GROUP 17, Emission Control System 

− Evaporative 

Emission Purge Solenoid Check 

P.17-62

.

Q: Is the evaporative emission purge solenoid normal?

YES : Go to Step 2.
NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

ACX01539

16-PIN

MB991502

AC

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SYMPTOM PROCEDURES

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STEP 2. Check the evaporative emission ventilation 
solenoid.
Refer to GROUP 17, Emission Control System 

− Evaporative 

Emission Ventilation Solenoid Check 

P.17-63

.

Q: Is the evaporative emission ventilation solenoid 

normal?
YES : Check the following items, and repair or replace the 

defective items.

a. Check for leaks from the vapor line or 

evaporative emission canister.

b. Check for leaks from the fuel tank.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair or replace. Then confirm that the malfunction 

symptom is eliminated.

INSPECTION PROCEDURE 26: Incorrect Idle Speed When the A/C is Operating (A/C Switch 2 Signal)

GREEN

AK201155

YELL

OW

-

RED

GREEN

6

AUTOMATIC
COMPRESSOR
CONTROLLER

POWERTRAIN
CONTROL
MODULE (PCM)

AUTOMATIC
A/C SYSTEM

MANUAL
A/C SYSTEM

78

A/C-ECU

9

6

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17

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2

3 4

7 8

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5

E-111

A/C Switch 2 Signal

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656667686970 717273
74757677787980 8182
8384

858687

8889

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6364

D-134

(MU803804)

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SYMPTOM PROCEDURES

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CIRCUIT OPERATION

• The PCM increases the engine idle speed by 

driving the Throttle actuator control motor when 
the automatic compressor-ECU sends a "A/C on" 
signal to the module.

• The automatic compressor-ECU detects how the 

air conditioning is applying load to the engine, 
and converts the information to a voltage signal 
(High voltage = low load, Low voltage = high 
load). This voltage signal is called "A/C switch 2 

signal". The PCM receives this A/C switch 2 sig-
nal from the automatic compressor-ECU through 
terminal No. 78, and determines the idle-up 
speed according to the high or low air condition-
ing load.

.

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

• Malfunction of the A/C control system.

• Open or shorted circuit, or improper connector 

contact.

• PCM failed. 

DIAGNOSIS

STEP 1. Check harness connector D-134 at PCM 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.

AK201038

CONNECTOR: D-134

AD

PCM

D-134(GR)

AK201060

E-111

AB

CONNECTOR: E-111

AK201166

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CONNECTOR: D-134

AB

PCM

D-134(GR)

HARNESS CONNECTOR: 
COMPONENT SIDE

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SYMPTOM PROCEDURES

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STEP 2. Measure the output voltage at PCM harness side 
connector D-134.
(1) Disconnect the connector D-134 and measure at the 

harness side.

(2) Start the engine and run at idle.
(3) Turn the A/C switch "ON".

(4) Measure the voltage between terminal No. 78 and ground.

• If atmospheric air temperature is 15°C (59°F) or less, 

the voltage should be 1 volt or less.

• If atmospheric air temperature is 18°C (65.4°F) or more, 

the voltage should be battery positive voltage.

(5) Turn the A/C switch "OFF".
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?

YES :  Replace the PCM. Then confirm that the malfunction 

symptom is eliminated.

NO :  Refer to GROUP 55, Introduction To Heater, Air 

Conditioning And Ventilation Diagnosis 

P.55A-5

.

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CONNECTOR: D-134

AB

PCM

D-134(GR)

HARNESS CONNECTOR: 
COMPONENT SIDE

AK201458

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D-134 HARNESS 
CONNECTOR: 
COMPONENT SIDE

AK201458AB

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