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Mitsubishi Montero (2004+). Manual - part 1086

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-55

• The center differential detection switch is defec-

tive.

• The 2WD detection switch is defective.

• The 4LLc detection switch is defective.

• The 4H detection switch 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 transfer
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 the transfer diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK (OFF)" position.
Q: Does the transfer set any DTC?

YES : Diagnose the transfer-ECU. Refer to

P.23A-401

NO : Go to Step 2.

STEP 2. Check M-ASTC-ECU connector E-121.

Q: Is M-ASTC-ECU connector E-121 in good condition?

YES : Go to Step 3.
NO : Repair or replace the connector, and then go to Step

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

AC204176

CONNECTOR: E-121

HARNESS SIDE

M-ASTC DIAGNOSIS

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MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-56

STEP 3. Check the wiring harness from the M-ASTC-ECU
connector E-121 (terminals 75, 80, 86, 76 and 87) to
2WD/4WD detection switch connector C-10 (terminal 1),
the center differential detection switch connector C-12
(terminal 1), the 2WD detection switch connector C-06
(terminal 1), the 4LLc detection switch connector C-05
(terminal 1) and 4H detection switch connector C-11
(terminal 1).

AC204510 AB

C-05(BR)

C-10(B)

C-12(BR)

C-06(B)

C-11(W)

CONNECTORS: C-05, C-06, C-10, C-11, C-12

C-06(B)

HARNESS SIDE

C-05(BR)

HARNESS SIDE

C-11(W)

HARNESS SIDE

C-12(BR)

HARNESS SIDE

C-10(B)

HARNESS SIDE

AC204194

CONNECTORS: E-121, E-123

E-123(GR)

E-123

HARNESS SIDE

E-121

HARNESS SIDE

9 8

1817

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-57

NOTE: Also check intermediate connector E-123 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector E-123 is damaged, repair
or replace the damaged component(s) as described in GROUP
00E, Harness Connector Inspection

P.00E-2

. If the connector

has been repaired or replaced, go to Step 4.
Q: Is the wiring harness from the M-ASTC-ECU connector

E-121 (terminals 75, 80, 86, 76 and 87) to 2WD/4WD
detection switch connector C-10 (terminal 1), the center
differential detection switch connector C-12 (terminal 1),
the 2WD detection switch connector C-06 (terminal 1),
the 4LLc detection switch connector C-05 (terminal 1)
and 4H detection switch connector C-11 (terminal 1) in
good condition?
YES : Replace the M-ASTC-ECU, and then go to Step 4.
NO : Repair the wiring harness, and then go to Step 4.

STEP 4. Recheck for diagnostic trouble code.
Q: Does DTC 75 reset?

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

DTC 81: G sensor not initialized
DTC 82: Yaw rate sensor not initialized

M-ASTC DTC SET CONDITION
DTCs 81 and 82 will be set when a new G and yaw
rate sensor is not initialized (i.e. reference point posi-
tioning) executing No.16 "G SNSR: " and No.15
"YAWRATE SNS: 0" on the Actuator test.

TROUBLESHOOTING HINTS
The most likely causes for DTC 81, 82 to set are:

• The G and yaw rate sensor 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: Set Harness

STEP 1. Initialize the G and yaw rate sensor. (Recheck for
diagnostic trouble code.

Initialize the G and yaw rate sensor (Refer to

P.35C-215

), and

check that the DTC sets.
Q: Does DTC 81 or 82 reset?

YES : Replace the G and yaw rate sensor. Refer to

P.35C-215

. Then go to Step 2.

NO : Go to Step 2.

M-ASTC DIAGNOSIS

TSB Revision

MITSUBISHI ACTIVE SKID AND TRACTION CONTROL SYSTEM

35C-58

STEP 2. Check the diagnostic trouble code.
Q: Does DTC 81 or 82 reset?

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

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:

• 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

STEP 1. Initialize the M-ASTC-ECU. (Recheck for
diagnostic trouble code).

Initialize the steering wheel sensor (Refer to

P.35C-216

), and

check that the DTC sets.
Q: Does DTC 83 reset?

YES : Replace the steering wheel sensor. Refer to

P.35C-216

. 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.

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.

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