Abs Does Not Operate

CAUTION: If Anti-Lock Brake System/Traction Control Electronic Control Unit (ABS/TRAC ECU) replacement is necessary during testing, always ensure ABS/TRAC ECU connectors and ground circuit are okay. If either is suspect, repair and repeat testing to confirm ABS/TRAC ECU malfunction.

Retrieve Diagnostic Trouble Codes (DTC). See RETRIEVING DIAGNOSTIC TROUBLE CODES under DIAGNOSIS & TESTING. If any DTCs are present, perform appropriate diagnostic test. If no DTCs are present, check IG power source circuit. See DTC 41: IG POWER SUPPLY CIRCUIT under DIAGNOSTIC TESTS. Check speed sensor circuits. Perform appropriate wheel speed sensor circuit test. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION table under DIAGNOSIS & TESTING. Check ABS/TRAC actuator. See ABS/TRAC ACTUATOR CHECK under COMPONENT TESTS. If ABS/TRAC actuator is not okay, check hydraulic system for leakage. If all preceding tests are okay and ABS still does not operate, replace ABS/TRAC ECU.