Initial Inspection and Diagnostic Overview
Inspection and Verification - NGSCommunication Check
1. Verify the customer concern by applying the brakes under different conditions.
2. Visually inspect for obvious signs of mechanical and electrical damage.
3. If the fault is not visually evident, connect New Generation STAR (NGS) Tester to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the NGS menu. If the NGS does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
4. If the NGS still does not communicate with the vehicle, refer to the New Generation STAR Tester manual.
5. Carry out the DATA LINK DIAGNOSTIC TEST. If the NGS responds with:
^ CKT914, CKT915, or CKT70 = ALL ECUS NO RESP/NOT EQUIP, refer to Module Communications Network.
^ NO RESP/NOT EQUIP for anti-lock brake control module, GO to Pinpoint Test A. A
^ SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTC'S), erase the continuous DTC'S and carry out self-test diagnostics for the anti-lock brake control module.
6. If the DTC'S retrieved are related to the concern, go to Anti-Lock Brake Control Module Diagnostic Trouble Code (DTC) Index to continue diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
7. If no DTC'S related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures
Inspection and Verification - Drive Cycle Test
The drive cycle test can be used as a system evaluation test or repair verification test, or during diagnosis (for intermittent concerns).
For system evaluation, the customer may only have a general concern about the way the vehicle is braking. There may not be a clear system concern to troubleshoot. This test is designed to produce common system concern symptoms. Once a symptom is found, a symptom diagnostic procedure can be followed to repair the vehicle.
Always use this test after vehicle repairs because the anti-lock brake control module is unable to detect some system concerns unless the vehicle is driven under specific conditions. After completing the drive cycle test, carry out the self-test using New Generation STAR (NGS) Tester.
NOTE: Wetting down the area where the stops are to be performed will aid in this test.
NOTE: An assistant should be used to monitor the wheels during the ABS stop. Momentary lockup is permissible.
1. While driving the vehicle approximately 16 km/h (10 mph), depress the brake pedal hard enough to lock all four wheels.
2. Does one wheel lock consistently?
^ If yes and the yellow ABS warning indicator is not illuminated, GO to Symptom Chart. Symptom Related Diagnostic Procedures
^ If yes and the yellow ABS warning indicator is illuminated, retrieve and document DTC'S. Proceed to Anti-Lock Brake Control Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
3. NOTE: If the pump motor turns on and the vehicle pulls immediately, the front anti-lock brake sensor opposite the pull should be checked using the ABS Misfire, ABS Too Sensitive, ABS Fires On Normal Stop procedure from the Symptom Chart. If the pump motor turns on and the vehicle does not pull, the rear anti-lock brake sensors should be checked using the ABS Misfire, ABS Too Sensitive, ABS Fires On Normal Stop procedure from the Symptom Chart. If the pump motor does not turn on and the vehicle pulls immediately, the system should be checked using the Vehicle Pulls During Braking procedure from the Symptom Chart.
NOTE: Turn off the windshield wipers.
While driving the vehicle approximately 32 km/h (20 mph), perform a light-to-medium (normal traffic) stop.
4. Does the pump motor turn on and are brake pedal pulsations felt at any time during the stop?
^ If yes and the yellow ABS warning indicator is not illuminated, GO to Symptom Chart.
^ If yes and the yellow ABS indicator does illuminate, retrieve and document DTC'S. Proceed to Anti-Lock Brake Control Module Diagnostic Trouble Code (DTC) Index.
5. Clear continuous DTC'S.
6. Start the vehicle and shift the transmission into low gear.
7. Allow the vehicle to creep forward at idle for at least 45 seconds.
8. Does the yellow ABS indicator illuminate?
^ If yes, retrieve and document DTC'S. Proceed to Anti-Lock Brake Control Module Diagnostic Trouble Code (DTC) Index.
9. Slowly accelerate to 40 km/h (25 mph). Let at least 45 seconds elapse before reaching 40 km/h (25 mph).
10. Does the yellow, ABS warning indicator illuminate?
^ If yes, retrieve and document DTC'S. Proceed to Anti-Lock Brake Control Module Diagnostic Trouble Code (DTC) Index.
11. Has the customer concern been addressed and corrected by the previous actions?
^ If yes, the system is OK.
^ If no, GO to Symptom Chart.