Mitsubishi Montero (2002-2004). Manual - part 710

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-537

STEP 8. Using scan tool MB991502, read the diagnostic 
trouble code (DTC).
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q:  Is DTC P0638 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

P0642 Throttle Position Sensor Power Supply

.

TECHNICAL DESCRIPTION

• PCM checks the TPS power voltage for abnormal 

conditions.

.

DTC SET CONDITIONS

Check Conditions

• Battery positive voltage is higher than 6.3 volts.

Judgement Criteria

• TPS power voltage should be 4.1 volts or less for 

0.5 seconds.

.

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

• PCM failed.

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) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P0642 set?

YES : Replace the PCM.
NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use Troubleshooting/
Inspection Service Points 

P.00-6

.

ACX01539

16-PIN

MB991502

AC

ACX01539

16-PIN

MB991502

AC

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-538

P0657 Throttle Actuator Control Motor Relay Circuit Malfunction

AK201461

TMROTTEL
ACTUATOR
CONTROL
MOTOR

THROTTEL ACTUATOR
CONTROL MOTOR
POWER SURCE

B-22X

B-23X

A-03

(MU802611)

WHITE-BLA

CK

WHITE-

BLA

CK

WHITE-

BLA

CK

WHITE-
BLACK

WHITE-

BLA

CK

SKY BLUE

To PCM

To PCM

MFI
RELAY

RED

RED

RED

FUSIBLE LINK(5)

2

3

6

4

1

4

3

2

1

15

132

D-136

D-132

1 2 3 4 5 6
7 8 9 10 11 12

1

2

3

4

1

2

3

4

POWERTRAIN
CONTROL
MODULE

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-539

.

CIRCUIT OPERATION

• Battery positive voltage is applied to the throttle 

actuator control motor relay terminal (terminal 
No. 3).

• Battery positive voltage is applied to the throttle 

actuator control motor relay terminal (terminal 
No. 4) from the MFI relay (terminal No. 1).

• PCM (terminal No. 15) applies current to the 

throttle actuator control motor relay coil by turning 
ON the  power transistor in the unit in order to 
turn the relay ON.

• When the throttle actuator control motor relay 

turns ON, battery positive voltage is supplied by 
the throttle actuator control motor relay (terminal 
No. 1) to the PCM (terminal No. 132).

.

TECHNICAL DESCRIPTION

• When the ignition switch ON signal is input into 

the PCM, the PCM turns ON the throttle actuator 
control  motor relay.

.

DTC SET CONDITIONS

Check Condition

• Ignition switch "ON" position.

Judgement Criteria

• The power line voltage of the electronic controlled 

throttle system should be 4.9 volts or less for 0.8 
seconds.

.

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

• Throttle actuator control motor relay failed or mal-

adjusted.

• Open or shorted throttle actuator control motor 

relay circuit, or loose connector.

• PCM failed.

AK201046

A-03(B)

AB

CONNECTOR: A-03

AK201171

B-23X

AB

CONNECTOR: B-23X

THROTTLE ACTUATOR
CONTROL MOTOR 
RELAY

AK201039

MFI RELAY

B-22X

AB

CONNECTOR: B-22X

AK201565

CONNECTORS: D-132, D-136

AB

PCM

D-132(GR) D-136(GR)

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-540

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

STEP 1. Check connector B-23X at throttle actuator control 
motor relay 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 go to Step 14.

AK201172

2 1

3

4

B-23X

AB

CONNECTOR: B-23X

HARNESS 
CONNECTOR: 
COMPONENT SIDE