Abs Self Diagnostics

ABS DTCs are set under different conditions, depending on malfunction detected. Most ABS DTCs will only set during vehicle operation. Some ABS DTCs will set immediately after the engine is started during the ABS self-check. When checking if an ABS DTC sets again after DTC has been erased, duplicate as closely as possible ABS DTC set conditions. Depending on the detection timing and set conditions for the specific ABS DTC, vehicle must either be driven or engine turned off and restarted.

Use following steps to plan diagnostic strategy:

1. Gather information about problem from the customer.
2. Verify that condition described by customer exists.
3. Using scan tool check for any ABS DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  .
4. If malfunction cannot be verified, and there are no ABS DTCs stored in memory, malfunction is intermittent. Perform preliminary check. See PRELIMINARY CHECK  under TROUBLE SHOOTING.
5. If malfunction can be verified, but there are no ABS DTCs stored in memory check that the basic brake system is operating properly. See appropriate DISC & DRUM article. If no problem with basic brake system is found or system cannot communicate with the scan tool, repair by symptom. See SYMPTOM TEST INDEX  under SYMPTOM TESTS.
6. If ABS related DTC's are stored in memory, record number of DTC(s), then erase DTC from the memory using the scan tool. See CLEARING DIAGNOSTIC TROUBLE CODES  . Recreate the ABS DTC set conditions to see if the same ABS DTC will set again. If DTC resets, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITION  .
7. If same DTC does not reset, malfunction is intermittent. Check for conditions that could cause intermittent condition. See PRELIMINARY CHECK  under TROUBLE SHOOTING.