Initial Inspection and Diagnostic Overview
Inspection and VerificationCommunication Check
1. Verify the customer concern by applying the brakes under different conditions.
2. Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
3. If the concern remains after the inspection, connect the diagnostic tool to the Data Link Connector (DLC) located beneath the instrument panel, and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connection of the DLC to the vehicle.
^ check that the ignition switch is in the RUN position.
4. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
5. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
^ CAN or ISO circuit fault; all electronic control units no response/not equipped, refer to Information Bus.
^ No response/not equipped for the ABS module; Refer to Pinpoint Test A. Test A: No Communication With the Anti-Lock Brake System (ABS) Module
^ System passed, retrieve and record the continuous Diagnostic Trouble Codes (DTC's), erase the continuous DTC's, and carry out the self-test diagnostics for the ABS module.
6. If the DTC's retrieved are related to the concern, go to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
7. If no DTC's related to the concern are retrieved; Refer 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 the diagnostic tool.
NOTE: Wetting down the area where the testing is to be carried out 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), press 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 the DTC's. Proceed to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
3. 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; Refer to Symptom Chart. Symptom Related Diagnostic Procedures
^ If yes and the yellow ABS indicator is illuminated, retrieve and document DTC's. Proceed to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
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 the DTC's. Proceed to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
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 the DTC's. Proceed to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index. Diagnostic Trouble Code Tests and Associated Procedures
11. Has the customer concern been addressed and corrected by the previous actions?
^ If yes, the system is OK.
^ If no; Refer to Symptom Chart Symptom Related Diagnostic Procedures