Symptom Diagnosis: INTERMITTENTS
Failures in anti-lock brakes may be difficult to diagnose accurately. If an ABS failure or fault occurs, ANTI-LOCK indicator will illuminate. If fault is an intermittent problem which has corrected itself (ANTI-LOCK indicator off), history trouble code will be stored.
Stored in history code will be history data of fault at time the fault occurred. FLASH CODE DIAGNOSTICS method can be used to identify stored history trouble codes, but Tech 1 must be used to read ABS history data. ABS self-diagnosis system can be used to help find suspected circuit.
- Record current codes and code history information. Record any descriptive driving circumstances during failure occurrence.
- Use Tech 1, mode F3 (ABS snapshot), while test driving vehicle. See USING TECH 1. Try to duplicate condition.
- If no trouble code is stored, it may be necessary to use SYMPTOM DIAGNOSTIC CHARTS.
Most intermittent problems are caused by faulty electrical connectors or wiring. When an intermittent failure is encountered, inspect suspected as follows:
- Check for poor mating of connector halves or terminals not fully seated in connector body (backed out).
- Check for improperly formed or damaged terminals. Carefully reform all connector terminals of problem circuit to increase contact tension.
- Check for poor terminal-to-wire connection. This requires removing terminal from connector body to inspect.