Inspection Procedure 12: With the rear differential lock being deactivated, the active stability control indicator lamp, active stability control-OFF indicator lamp, ABS warning lamp, and brake warning lamp illuminate at the same time.


















COMMENT ON TROUBLE SYMPTOM

  • While the rear differential lock is being switched or activated, the Active stability control indicator lamp, the ASC OFF indicator lamp, the ABS warning lamp, and brake warning lamp illuminate at the same time.
  • The rear differential lock detection circuit may have an abnormality.

PROBABLE CAUSES

  • Damaged wiring harness and connectors
  • Malfunction of the rear differential lock engage switch
  • The ASTC-ECU is defective.

DIAGNOSIS

STEP 1. M.U.T.-III data list
(1)Ignition switch: ON
(2)Operate the rear differential lock switch, and check if the operation status matches the service data output.

  • Item 85: Rear differential lock
OK:
    (Rear differential lock activated): LOCK
    (Rear differential lock deactivated): UNLOCK

  • Item 86: Rear differential lock switch:
OK:
    (Rear differential lock activated): ON
    (Rear differential lock deactivated): OFF

  • Item 87: Rear differential lock indicator
OK:
    (Rear differential lock activated): ON
    (Rear differential lock deactivated): OFF

Q. Is the check result normal?
Go to Step 5.
NO (Item 85 or 86 output unmatched) : Go to Step 2.
NO (Item 87 output unmatched) : Go to Step 4.

STEP 2. Check the wiring harness between D-223 ASTC-ECU connector, E-116-1 rear differential lock switch connector <3200-M/T> and E-116 rear differential lock switch connector <3000, 3200-A/T, 3800> for open or short circuit.
note Before checking the wiring harness, check D-34 joint connector, and D-219, D-230, E-120, E-116 <3200-M/T> intermediate connectors, and then repair if necessary.
Check the wiring harness between D-223 ASTC-ECU connector (terminal No. 78), E-116-1 rear differential lock switch connector (terminal No. 1) <3200-M/T> or E-116 rear differential lock switch connector (terminal No. 1) <3000, 3200-A/T, 3800>.

Q. Is the check result normal?
Go to Step 3.
Repair the wiring harness.

STEP 3. Check the rear differential lock switch.
Refer to GROUP 27 - Rear Differential Lock Switch Check .

Q. Is the check result normal?
Go to Step 6.
Replace the rear differential lock switch.

STEP 4. Check the wiring harness between D-223 ASTC-ECU connector and D-124 transfer-ECU connector for open or short circuit.
note Before checking the wiring harness, check D-225 intermediate connector, and then repair if necessary.
Check the wiring harness between D-223 ASTC-ECU connector (terminal No. 85) and D-124 transfer-ECU connector (terminal No. 6).

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 5. Check the rear differential lock ECU.
Refer to GROUP 27 - Rear Differential Lock ECU Inspection .

Q. Is the check result normal?
Go to Step 6.
Replace the rear differential lock ECU.

STEP 6. Retest the system.

Q. Is the check result normal?
Replace the ASTC-ECU. Then go to Step 7.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

STEP 7. Retest the system.

Q. Is the check result normal?
Return to Step 1.
This diagnosis is complete.