Anti-Lock Brake System: Diagnosis: INTERMITTENTS

There are 2 types of trouble codes: current and history codes. Current codes indicate existing failures, while history codes indicate intermittent failure. Fault must be present during testing in order to correctly locate problem.

Most intermittent problems are caused by faulty electrical connections or wiring. When an intermittent failure is encountered, visually inspect suspect circuits for the following conditions.

• Check for poor mating of connector halves or terminals not fully seated in connector body (backed out).
• Check for improperly formed or damaged terminals. All connector terminals in a problem circuit should be carefully reformed to increase contact tension.
• Check for poor terminal-to-wire connection. Terminal and wire need to be removed from connector body for inspection.

If visual inspection does not help locate intermittent problem, use ABS self-diagnostic system to identify suspect circuit. Before using codes to diagnose intermittent failure, perform the following steps:

• Display and then clear ABS trouble codes in Electronic Brake Computer Module/Electronic Brake Traction Control Module (EBCM/EBTCM).
• Test drive vehicle, and attempt to duplicate conditions causing problem or complaint. Stop vehicle, and record any codes set.

The following conditions may cause intermittent operation of ANTI-LOCK warning light:

• Low Or Intermittent Voltage At EBCM/EBTCM
• Low Brake Fluid Or Low Fluid Pressure
• Interruption Of Power To EBCM/EBTCM Or Hydraulic Pump Motor Circuits Main Relay, Pump Motor Relay, Fuses And Related Wiring