INTERMITTENTS & Poor Connections

Failures in ABS/TCS may be difficult to diagnose accurately. If an ABS/TCS failure or fault occurs, ANTI-LOCK and/or TRACTION OFF indicator will illuminate. If fault is an intermittent problem which has corrected itself (ANTI-LOCK and/or TRACTION OFF indicator off), DTC will be stored.

ABS/TCS self-diagnostic system can be used to help identify suspect circuit. Perform following procedure:

• Display and record DTC history data. Record any descriptive driving circumstances during failure occurrence. Clear any ABS/TCS DTCs set in EBCM/EBTCM.
• Test drive vehicle. Attempt to repeat failure under condition in which failure occurred. Use Tech 1 scan tool, mode F3 (snapshot), while test driving vehicle. See USING TECH 1 SCAN TOOL.
• After duplicating condition, stop vehicle and display any ABS/TCS DTCs which may have been stored.
• If no trouble codes were stored, see SYMPTOM TESTS  for diagnosis by symptom.

Most intermittent problems are caused by faulty electrical connectors or wiring. When an intermittent failure is encountered, check suspect circuits for:

• Poor mating of connector halves, or terminals not fully seated in connector body (backed out).
• Improperly formed or damaged terminals. All connector terminals in a problem circuit should be carefully reformed to increase contact tension.
• Check for dirt or corrosion on terminals, which could impede proper terminal contact.
• Poor terminal-to-wire connection. This requires removing terminal from connector body to inspect.
• Wheel speed sensor cables not attached in retainers or routed too close to spark plug wires.
• Low system voltage. If low system voltage is detected at EBCM/EBTCM, ABS will turn on ANTI-LOCK indicator until normal system voltage is achieved.