Inspection Procedure 1

Inspection Procedure 1: Scan tool cannot communication only with ASC-ECU.

TECHNICAL DESCRIPTION (COMMENT)
When scan tool cannot communicate with the ABS/TCL/ASC system, the CAN bus line, ASC-ECU power supply circuit system, or ASC-ECU may be faulty.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Damaged wiring harness and connectors
^ ASC-ECU malfunction
^ Wrong routing of M.U.T.-III harness
^ Abnormality in battery or generator
^ Abnormality in power supply voltage to ASC-ECU
^ ECU malfunction of other system

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. M.U.T.-III CAN bus diagnostics
Use scan tool to diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Check and repair the power supply circuit system. Then go to Step 2.
NO: Repair the CAN bus lines. Then go to Step 2.

STEP 2. Retest the system
Check the communication with the scan tool.
Q: Is the check result normal?
YES: This diagnosis is complete.
NO: Replace the ASC-ECU.