Note on Intermittents

Intermittent failures in the anti-lock brake system may be difficult to accurately diagnose. The ABS trouble codes which may be stored by the EBCM are not specifically designated as ``CURRENT'' or ``HISTORY'' codes as are BCM and ECM codes. These codes, however, can be helpful in diagnosing intermittent conditions. If an intermittent condition is to be diagnosed, the ABS self-diagnostic system can be used in the following manner to help isolate the suspected circuit:
1. First, display and clear any ABS trouble codes which may be present in the EBCM.
2. Test drive the vehicle, attempting to repeat the failure condition.
3. After duplicating the condition, stop the vehicle and display any ABS trouble codes which may have been stored.
4. If no trouble codes were stored, it may become necessary to refer to ABS SYMPTOM DIAGNOSIS.

If an intermittent fault cannot be otherwise diagnosed, the problem will most probably be caused by a defective electrical connection or wiring. When an intermittent problem is encountered, check questionable circuits and electrical connectors for the following:
1. Poor mating of connector halves or terminals not fully seated in connector body.
2. Improperly formed or damaged terminals. All connector terminals in the problem circuit should be carefully removed to increase contact tension.
3. Poor terminal wire connection.

The following conditions which could possibly cause intermittent operation of the BRAKE and ANTI-LOCK lamps are as follows:
1. Low system voltage - if low system voltage is detected at the EBCM, the ANTI-LOCK lamp will illuminate until normal system voltage is obtained.
2. Low brake fluid - low brake fluid will cause the BRAKE and ANTI-LOCK lamps to illuminate. When the fluid level sensor indicates an acceptable fluid level, normal system operation will resume.
3. Low accumulator pressure - low accumulator pressure will cause the BRAKE and ANTI-LOCK lamps to illuminate. When normal operating pressure is obtained, normal system operation will resume.
4. Any condition which results in interruption of power to the EBCM or hydraulic unit - main relay, pump motor relay, fuse and related wiring circuits.