Inspection and Verification - Drive Cycle Test: Notes
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.
- While driving the vehicle approximately 16 km/h (10 mph), press the brake pedal hard enough to lock all four wheels.
- Does one wheel lock consistently?
- If yes and the yellow ABS warning indicator is not illuminated, GO to SYMPTOM CHART .
- If yes and the yellow ABS warning indicator is illuminated, retrieve and document the DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- While driving the vehicle approximately 32 km/h (20 mph), perform a light-to-medium (normal traffic) stop.
- 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 is illuminated, retrieve and document DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- Clear continuous DTCs.
- Start the vehicle and shift the transmission into low gear.
- Allow the vehicle to creep forward at idle for at least 45 seconds.
- Does the yellow ABS indicator illuminate?
- If yes, retrieve and document theDTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- Slowly accelerate to 40 km/h (25 mph). Let at least 45 seconds elapse before reaching 40 km/h (25 mph).
- Does the yellow ABS warning indicator illuminate?
- If yes, retrieve and document the DTCs. Proceed to the ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX .
- Has the customer concern been addressed and corrected by the previous actions?
- If yes, the system is OK.
- If no, GO to SYMPTOM CHART .