Initial Inspection and Diagnostic Overview
Inspection and VerificationNOTE: If a new anti-lock brake system (ABS) module is installed, it must be configured. If equipped with stability assist, the ABS module must also be calibrated. Follow the diagnostic tool directions.
1. Verify the customer concern.
2. Verify the stoplamps operate correctly by pressing and releasing the brake pedal with the ignition switch in the OFF position.
If the stoplamps operate correctly, proceed to the next step.
3. Verify that the PRNDL operates correctly on the instrument cluster. If the PRNDL operates correctly, proceed to the next step.
4. Visually inspect for obvious signs mechanical or electrical damage.
Visual Inspection Chart
5. If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) 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 connections to the vehicle.
^ check the ignition switch position.
6. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
NOTE: If equipped with stability assist, the vehicle must be at a complete standstill when carrying out the self test. Any movement of the vehicle during the self test may result in false DTCs being set.
7. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
^ CAN, ISO, or UBP circuit fault; all electronic control units no response/not equipped, refer to Information Bus.
^ No response/not equipped for the ABS module, GO to Pinpoint Test A. A: No Communication With the Anti-Lock Brake Control Module
^ System passed, retrieve and record the continuous Diagnostic Trouble Codes (DTCs), erase the continuous DTCs, and carry out self test diagnostics for the ABS module.
8. If the DTCs retrieved are related to the concern, go to the Anti-Lock Brake System (ABS) Module Diagnostic Trouble Code (DTC) Index [1][2]Diagnostic Trouble Code Descriptions to continue diagnosis.
9. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures
NOTE: The need to calibrate the module is indicated by the active/fail lamp flashing. There are other service actions that can require calibration when there is no flashing lamp. The lamp flashes after clearing the DTCs that are indicated in the ABS module calibration list.
NOTE: Always retrieve the continuous DTCs after running the self test.
NOTE: For a complete master list of DTCs, refer to Body Control Systems.
NOTE: If DTC B2900, C1805, and U1900 are set at the time, diagnose the concern for U1900 first.
NOTE: DTC C1730 (Reference Voltage Out Of Range) must be repaired before DTCs C1279, C1280, C1281, C1282, C1288, or C1289.