Abs Does Not Operate Efficiently

CAUTION: If ABS ECU replacement is necessary during testing, always ensure ABS ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ABS ECU malfunction.

Retrieve Diagnostic Trouble Codes (DTC). See RETRIEVING DIAGNOSTIC TROUBLE CODES under DIAGNOSIS & TESTING. Check speed sensor circuits. See DTC 31-34: SPEED SENSOR CIRCUIT under DIAGNOSTIC TESTS. Check brakelight switch circuit. See BRAKELIGHT SWITCH CIRCUIT under COMPONENT TESTS. Check ABS actuator. See ABS ACTUATOR CHECK under COMPONENT TESTS. If ABS actuator is okay, check hydraulic system for leaks. See Figure. If all listed items test okay, replace ABS ECU.