Inspection Procedure 7: ABS System Inoperative

Inspection Procedure 7: ABS System Inoperative.

CAUTION
If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.

TECHNICAL DESCRIPTION (COMMENT)
In case of this trouble symptom, ABS system operation may be disabled. Diagnostic trouble code may be set by the ABS system using scan tool.

PROBABLE CAUSES
^ Low battery voltage
^ Wiring harness or connector failure of CAN bus line
^ ABS-ECU malfunction

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: Go to Step 2.
NO: Repair the CAN bus lines. On completion, go to Step 2.

STEP 2. Diagnostic trouble code check after resetting CAN bus lines
Q: Is any DTC set?
YES: Carry out the relevant troubleshooting.
NO: Go to Step 3.

STEP 3. Hydraulic unit (HU) check
Refer to HYDRAULIC UNIT CHECK. Testing and Inspection
Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair the brake pipe or replace ABS-ECU.

STEP 4. Operation check
Q: Does ABS operate normally?
YES: The procedure is complete.
NO: Check the brake system related components except the ABS system.