GM Service Manual Online
For 1990-2009 cars only

Intermittent malfunctions may be difficult to accurately diagnose. Use the following method in order to attempt to isolate an intermittent malfunction.

The following method assists in isolating an intermittent malfunction. The following method is especially useful for identifying intermittent malfunctions in wheel speed sensor circuitry.

If a malfunction occurs in the ABS, the amber ABS warning indicator will turn on during the ignition cycle during which the malfunction is detected.

A diagnostic trouble code will store under the following conditions:

    • The malfunction is intermittent.
    • The malfunction seems to have corrected itself.

The history data of the DTC at the time when the malfunction occurs will also be stored.

Use the Scan Tool in order to read ABS history data.

Faulty electrical connections or wiring cause most intermittents. Refer to Troubleshooting Procedures in Electrical Diagnosis for a detailed explanation of how to locate and repair intermittent conditions.