DTC 75: Defective transfer switch: 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 connecting 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.
Fig 1: Connecting Scan Tool To Data Link Connector
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Q: Does the transfer set any DTC?
1. YES: Diagnose the transfer-ECU. Refer to TRANSFER DIAGNOSIS < ACTIVE TRAC AWD II > .
2. NO: Go to Step 2.
STEP 2. Check M-ASTC-ECU connector E-121.

Fig 2: Identifying Connector E-121
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Q: Is M-ASTC-ECU connector E-121 in good condition?
1. YES: Go to Step 3.
2. NO: Repair or replace the connector, and then go to Step 4.
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).
NOTE: Also check intermediate connector E-123 for loose, corroded, 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 HARNESS CONNECTOR INSPECTION . If the connector has been repaired or replaced, go to Step 4.

Fig 3: Identifying Connectors C-05, C-06, C-10, C-11, C-12
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Fig 4: Identifying Connectors E-121/123
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

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?
1. YES: Replace the M-ASTC-ECU, and then go to Step 4.
2. NO: Repair the wiring harness, and then go to Step 4.
STEP 4. Recheck for diagnostic trouble code.
Q: Does DTC 75 reset?
1. YES: Return to Step 1.
2. NO: The procedure is complete.