Inspection Procedure 9: The Skid Control/TCL System Cannot Be Disabled When ASC Off Switch Is Pressed For 3 Seconds or More

Inspection Procedure 9: The skid control/TCL system cannot be disabled when ASC OFF switch is pressed for 3 seconds or more to turn the system OFF.





CAUTION
^ If there is any problem in the CAN bus lines, an incorrect DTC may be set. Prior to this diagnosis, diagnose the CAN bus lines.
^ Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION
^ ETACS-ECU terminal No.15 is grounded by pressing ASC OFF switch. The ON/OFF state of ASC OFF switch is transferred from ETACS-ECU to ASC-ECU via CAN bus line.
^ When the ASC OFF switch is pressed for 3 seconds or more, the ASC system turns OFF.
^ When the ASC OFF switch is pressed and held for 15 seconds or more, ASC turns ON.

COMMENTS ON TROUBLE SYMPTOM
This may be caused by the open circuit in the ASC OFF switch circuit.

PROBABLE CAUSES
^ Damaged wiring harness and connectors
^ ASC OFF switch malfunction
^ Malfunction of ETACS-ECU

DIAGNOSIS

Required Special Tools:
^ MB991958: Scan Tool (M.U.T.-III Sub Assembly)
^ MB991824: Vehicle Communication Interface (V.C.I.)
^ MB991827: M.U.T.-III USB Cable
^ MB991910: M.U.T.-III Main Harness A

STEP 1. ASC OFF switch check

Q: Is the check result normal?
YES: Go to Step 2.
NO: Replace ASC OFF switch. Then go to Step 6.

STEP 2. Connector check: C-313 ETACS-ECU connector, C-36 intermediate connector, C-45 ASC OFF switch connector

Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the damaged connector.

STEP 3. Wiring harness check between C-313 ETACS-ECU connector terminal No.15 and C-45 ASC OFF switch connector terminal No.1
^ Check the power supply circuit for open circuit.

Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair the wiring harness between C-313 ETACS-ECU connector terminal No.15 and C-45 ASC OFF switch connector terminal No.1.

STEP 4. Wiring harness check between C-45 ASC OFF switch connector terminal No.2 and the body ground
^ Check the ground wires for open circuit.

Q: Is the check result normal?
YES: Go to Step 5.
NO: Repair the wiring harness between C-45 ASC OFF switch connector terminal No.2 and the body ground.

STEP 5. Retest the system.

Q: Does ASC turn ON and OFF normally using ASC OFF switch?
YES: Intermittent malfunction.
NO: Replace the ETACS-ECU. Then go to Step 6.

STEP 6. Retest the system.

Q: Does ASC turn ON and OFF normally using ASC OFF switch?
YES: The procedure is complete.
NO: Return to Step 1.