Reading and Clearing Diagnostic Trouble Codes

NOTE: This procedure MUST be performed FIRST. Failure to do so may result in an incorrect diagnosis, wasted time and unnecessary replacement of good components. The System Pre-Check is used to screen the vehicle for relatively simple diagnostic repairs such as loose connectors, blown fuses, etc. However, the System Pre-Check is also used to prepare the vehicle for further diagnostics. In addition, anti-lock brake warning indicator concerns are addressed in this check.

System Pre-Check

SPC1 - Check Anti-Lock Brake Warning indicator Prove Out
- Turn ignition switch to "RUN".
- Observe the Anti-Lock Brake Warning Indicator.
- Did the ABS warning indicator come "ON" and go "OFF" after approximately two seconds?
YES - Prove out normal. Go to SPC3.
NO - If indicator stayed "ON", go to SPC3.
- If indicator never came "ON", go to SPC2.

SPC2 - Check ABS Warning Indicator
- Turn ignition switch to "OFF".
- Disconnect connector C386 front anti-Lock control module and connect breakout box and adapter.
- Connect a jumper wire between breakout box pins 1 and 17.
- Observe operation of ABS Warning Indicator.
- Turn ignition switch to "RUN".
- After ten seconds, turn ignition switch to "OFF".
- Did the anti-lock brake warning indicator illuminate?
YES - Replace the anti-lock brake control module. Go to SPC3.
NO - Diagnose anti-lock brake warning indicator for a bad bulb or wiring.

SPC3 - Retrieve Diagnostic Trouble Codes (DTC's)
- Connect scan tool to Data Link Connector (DLC).
- Turn ignition switch to "RUN".
- Retrieve DTC's using scan tool.
- Turn ignition switch to "OFF".
- Are any DTC's present?
YES - Staring with the first code recorded, go to the Diagnostic Trouble Code Index. Diagnostic Trouble Code Descriptions
NO - System Pass is obtained and no DTC's are present. Restore vehicle and test drive the vehicle to check ABS operation. If previous action was taken during the Inspection And Verification, the concern is most likely resolved. If the concern is still present after the road test, go to Diagnosis By Symptom. Symptom Related Diagnostic ProceduresIf no response is obtained, go to Pinpoint Test AB. AB No NGS Response