INTERMITTENTS & Poor Connections

Failures in ABS/TCS may be difficult to diagnose accurately. If an ABS/TCS failure or fault occurs, ABS and/or TCS warning indicator will illuminate. If fault is an intermittent problem which has corrected itself (ABS and/or TCS warning 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 2 scan tool, SNAPSHOT MODE, while test driving vehicle. See USING TECH 2 SCAN TOOL.
• After duplicating condition, stop vehicle and display any ABS/TCS DTCs which may have been stored.
• If no trouble codes were stored, perform SYMPTOM TESTS as necessary.

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 ABS warning indicator until normal system voltage is achieved.