Mitsubishi Montero (2002-2004). Manual - part 842

AUTO-CRUISE CONTROL

TSB Revision

ENGINE AND EMISSION CONTROL

17-31

STEP 7. Check the harness for an open circuit or damage 
between stoplight switch connector D-123 terminal 3 and 
PCM connector D-133 terminal 54.
Q: Is the harness wire in good condition?

YES : Go to Step 8.
NO :  Repair or replace the harness wire.

1

2

3

4

AC204682AB

CONNECTOR: D-123

D-123 

AC205046

CONNECTOR: D-133

D-133(GR)

PCM

AB

AUTO-CRUISE CONTROL

TSB Revision

ENGINE AND EMISSION CONTROL

17-32

STEP 8. Check the resistance of the ground circuit at 
stoplight switch connector D-123.
(1) Disconnect stoplight switch connector D-123 and measure 

at the harness side.

(2) Check the resistance between terminal 4 and ground.

• The resistance should measure less than 2 ohms.

Q: Is the resistance less than 2 ohms?

YES : Go to Step 10.
NO :  Go to Step 9.

STEP 9. Check the harness for an open circuit or damage 
between stoplight switch connector D-123 terminal 4 and 
ground.
Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO :  Repair or replace the harness wire.

1

2

3

4

AC204682AB

CONNECTOR: D-123

D-123 

2

1

3

4

AC205056AB

D-123 HARNESS
CONNECTOR: 
COMPONENT SIDE

1

2

3

4

AC204682AB

CONNECTOR: D-123

D-123 

AUTO-CRUISE CONTROL

TSB Revision

ENGINE AND EMISSION CONTROL

17-33

STEP 10. Check the stoplight switch.
(1) Disconnect stoplight switch connector D-123.
(2) Remove the stoplight switch and measure at the stoplight 

switch side.

(3) Measure the resistance value between terminals 3 and 4.

• The resistance value should measure two ohms or less 

when the plunger is pushed within 4.5 mm (0.2 inch) 
from the outer case end.

Q: Does the resistance value measure two ohms or less 

when the plunger is pushed within 4.5 mm (0.2 inch) 
from the outer case end?
YES : Go to Step 11.
NO :  Replace the stoplight switch. Refer to GROUP 35A, 

Brake Pedal 

P.35A-132

.

1

2

3

4

AC204682AB

CONNECTOR: D-123

D-123 

1

2

3

4

ACX01917

D-123 STOPLIGHT 
SWITCH CONNECTOR

AG

AC205057    

CONTINUITY

NO
CONTINUITY

4.5 mm (0.2 in)

AB

AUTO-CRUISE CONTROL

TSB Revision

ENGINE AND EMISSION CONTROL

17-34

STEP 11. Using scan tool MB991502, check data list item 
06: Stoplight Switch.

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) Set scan tool MB991502 to data reading mode for auto-

cruise control system item 06, Stoplight Switch.

• When the brake pedal is depressed, the display on scan 

tool MB991502 should be "ON."

• When the brake pedal is not depressed, the display on 

scan tool MB991502 should be "OFF."

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch operating properly?

YES : It can be assumed that this malfunction is intermittent. 

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

− How to Cope with 

Intermittent Malfunction 

P.00-6

.

NO :  Replace the PCM. Refer to 

P.17-54

, Auto-cruise 

Control.

DTC 23: Powertrain Control module (PCM) and Its Related Components

.

DTC SET CONDITIONS
This DTC is set when there is an failure in the PCM 
and its related components.

.

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

• Malfunction of the MFI system.

• Malfunction of the A/T system.

• Malfunction of the PCM.

DIAGNOSIS

Required Special Tool:

• MB991502: Scan Tool (MUT-II)

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

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) Check for MFI system diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?

YES : Refer to GROUP 13A, Diagnosis 

− Diagnostic 

Trouble Code Chart 

P.13Ab-22

.

NO :  Go to Step 2.

ACX02258AC

MB991502

16-PIN

ACX02258AC

MB991502

16-PIN