Mitsubishi Montero (2002-2004). Manual — part 1110

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-57

DTC 83: Steering wheel sensor not initialized

.

M-ASTC DTC SET CONDITION
DTC 83 will be set when the battery is removed and
then the neutral point of the steering wheel sensor is
erased. The Active skid control system OFF indicator
light may also be illuminated.

.

TROUBLESHOOTING HINTS
The most likely causes for DTC 83 to set are:

• The steering wheel sensor is defective

• The M-ASTC-ECU is defective.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

STEP 1. Make the system learn the neutral point of the
steering wheel sensor.
Make the system learn the neutral point by following the proce-
dure below.

Using scan tool MB991502

1. Connect scan tool MB991502 to the data link connector.

2. Turn the ignition switch to the "ON" position.
3. Turn the steering wheel 8

°or more, and then return it to the

neutral (straight forward) position.

4. Execute item No.14 "ST SNSR: 0 " on the Actuator test.
5. Ensure that the Active skid control system OFF indicator

light is off.

6. Turn the ignition switch to the "LOCK" (OFF) position.
7. Disconnect scan tool MB991502.

Not using scan tool MB991502

CAUTION

1. If a different diameter or size of tires are equipped, the M-

ASTC-ECU may not learn the neutral position.

Turn the steering wheel 8

°or more, and then return the

steering wheel to straight-ahead position.

2. Drive the vehicle straight forward at 35 km/h (25 mph) for

approximately one second.

3. Ensure that the Active skid control system OFF indicator

light is off.

Q: Does the M-ASTC-ECU set DTC 83?

YES : Replace the steering wheel sensor. Refer to

P.35C-

207

. then go to STEP 2.

NO : Go to Step 2.

STEP 2. Check the diagnostic trouble code.
Q: Does DTC 83 reset?

YES : Replace the M-ASTC-ECU.
NO : The procedure is complete.

ACX01539AE

MB991502

16-PIN

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-58

DTC 84: Transfer switch not initialized

.

CIRCUIT OPERATION
If the transfer gear is engaged, a relevant switch is
turned on. When the switch is turned on, the current
from the M-ASTC-ECU is grounded.

.

M-ASTC DTC SET CONDITION
DTC 84 will be set when a new M-ASTC-ECU is not
initialized.

.

TROUBLESHOOTING HINTS
The most likely causes for DTC 84 to set are:

• The transfer switch information in the M-ASTC-

ECU is not initialized.

• The M-ASTC-ECU is defective.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

Initialize the M-ASTC-ECU.
Initialize the M-ASTC-ECU. Refer to

P.35C-205

.

Q: Is DTC 84 set again?

YES : Replace the M-ASTC-ECU.
NO : Retest the system.

DTC 85: Master cylinder pressure sensor not initialized

.

CIRCUIT OPERATION
The pressure sensor, which is energized by the M-
ASTC-ECU, monitors the brake fluid pressure
applied by the master cylinder. If this pressure
becomes low, the signal from this pressure sensor
turns on the pressure switch.

.

M-ASTC DTC SET CONDITION
DTC 85 will be set when a new M-ASTC-ECU is not
initialized.

.

TROUBLESHOOTING HINTS
The most likely causes for DTC 84 to set are:

• M-ASTC-ECU not initialized

• The M-ASTC-ECU is defective.

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB991502: Scan Tool (MUT-II)

Initialize the M-ASTC-ECU.
Initialize the M-ASTC-ECU. Refer to

P.35C-205

.

Q: Is DTC 85 set again?

YES : Replace the M-ASTC-ECU.
NO : Retest the system.

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-59

CAN BUS LINE DIAGNOSTICS

Precautions on how to repair the CAN communication lines

M1353006000016

.

Precautions on how to repair the CAN bus lines

• If the CAN_L or CAN_H line on the main bus line

or branch line is repaired, renew all the twisted
wires between the end connectors. If the wiring
harness is partially repaired, or only CAN_L or
CAN_H line is repaired, noise suppression is
deteriorated, causing a communication error.

• If the connector or wire on the main bus line or

the branch wire is replaced, the frayed end of the
twisted wire should be within 10 cm (4.0 inches)
from the connector. If it exceeds 10 cm (4.0
inches), twist the wiring harness just like the orig-
inal twisted wire. If the frayed end exceeds 10 cm
(4.0 inches), noise suppression is deteriorated,
causing a communication error.

• If a branch wire is repaired, splice a new wire

directly into the main bus line. If a new wire is
spliced into the branch line, which is connected to
another device, a CAN communication error will
be caused.

.

Precautions on how to repair the terminator
resistor
If one-side terminator resistor is broken, the CAN
communication will continue although noise suppres-
sion is deteriorated. In this case, no DTC may be set.
Check the system regardless of whether a DTC is
set or not. If any damage is found, replace the termi-
nator resistor.

AC204696

ADDED WIRE

NO GOOD

AB

AC203824

CONNECTOR

TWISTED WIRE

AB

10 cm
(4.0 inches)

AC202856

ECU

ECU

ECU

ECU

GOOD

NO GOOD

TERMINATOR RESISTOR

OPEN
CIRCUIT
POINT

OPEN
CIRCUIT
POINT

TERMINATOR RESISTOR

AB

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-60

Diagnostic Item 1: CAN main bus line diagnostics

CAUTION

Before checking CAN bus lines and their inter-
connected components, "ground" yourself, by
touching a metal object such as an unpainted
pipe, this will discharge any potentially damag-
ing static that may have built up.

CAUTION

When measuring resistance value or voltage in
CAN bus lines, use a digital multimeter. If not
using a digital multimeter, the equipments con-
nected through the CAN bus lines may be dam-
aged.

CAUTION

Disconnect the negative battery terminal when
measuring the resistance value in the CAN bus
line. If you fail to do so, the equipments con-
nected through the CAN bus lines may be dam-
aged.

CAUTION

Always use the test harness when measuring the
voltage or resistance at the female connector. If
you fail to do so, connectors may be damaged.