Mitsubishi Montero (2004+). Manual - part 1077

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-19

DTC 36, 38: Communication error in power control module

CAUTION

If the diagnostic trouble code(s), which indicate a communication error in the power control module, 
has been set, diagnose the CAN main bus line.

.

CIRCUIT OPERATION
The M-ASTC-ECU gathers information regarding the 
engine and automatic transmission, through the CAN 
bus line from the power control module.

.

M-ASTC DTC SET CONDITION
DTC 36 is set if the M-ASTC-ECU cannot gather all 
information regarding the engine from the PCM. DTC 
38 is set if the ECU cannot gather all information 
regarding the automatic transmission from the PCM.

.

TROUBLESHOOTING HINTS
The most likely causes for DTC 36, 38 to set are:

• The CAN bus line is defective.

• Damaged connector(s)

• The power control module is defective

• The M-ASTC-ECU is defective.

DIAGNOSIS 

Required Special Tools:

•  MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991223: Harness Set

AC205062

CAN Bus Communication Circuit (powertrain control module)

AB

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-20

STEP 1. CAN main bus line diagnostics

CAUTION

If DTC 36 or 38 is set, diagnose the CAN main bus line.
Diagnose the CAN main bus line. Refer to 

P.35C-61

.

If the CAN main bus line is repaired, check that the diagnostic 
trouble code resets.
Q: Have you completed checking or repairing the CAN 

main bus line?
YES (If the CAN main bus line is repaired) : Go to Step 3.
YES (If the CAN main bus line is not defective) : Go to 

Step 2.

NO :  Diagnose the CAN main bus line. Refer to 

P.35C-61

.

STEP 2. Using scan tool MB991958, read the MFI 
diagnostic trouble code.

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 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the MFI DTC is set.
(4) Turn the ignition switch to the "LOCK (OFF)" position.
Q: Are MFI DTCs set?

YES : Diagnose the power control module. Refer to 

P.13A-26

.

NO :  Replace the M-ASTC-ECU, and then go to Step 3.

STEP 3. Recheck for diagnostic trouble code.
Q: Does DTC 36 or 38 reset?

YES : Return to Step 1.
NO :  The procedure is complete.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-21

DTC 47: Defective Cut Valve
DTC 48: Defective Pressure-increase Valve

.

CIRCUIT OPERATION
As the ignition switch is turned ON, power is supplied 
to each solenoid valve via the valve relay. 
M-ASTC-ECU, by turning ON the transistor, grounds 
the circuit and turns the solenoid valve ON.

.

M-ASTC DTC SET CONDITIONS
The M-ASTC-ECU constantly monitors the solenoid 
valve drive circuits. These codes are output if the 
M-ASTC-ECU judges that there is an open circuit or 
short-circuit in a solenoid coil or harness because the 
solenoid valve is on but no current flows to the sole-
noid valve, or if current continues flowing to the sole-
noid valve even though the solenoid valve is off.

.

AC205065

Cut Valve and PI Valve Circuit

AB

AC204169 AC

CONNECTORS: B-14, B-18

B-14(B)

B-18(B)

AC204176

CONNECTOR: E-119

AN

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-22

TROUBLESHOOTING HINTS (The most likely 
causes for these DTCs to set are:)

• The hydraulic brake booster (HBB) is defective.

• Damaged harness wires and connectors

• The M-ASTC-ECU is defective.

DIAGNOSIS

Required Special Tools:

•  MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991223: Harness Set

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code.

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 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the MFI DTC is set.
(4) Turn the ignition switch to the "LOCK (OFF)" position.
Q: Does the M-ASTC-ECU set any other DTCs than 47 or 

48?
YES : First diagnose the other DTCs (Refer to 

P.35C-7

).

YES : Go to Step 2.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR