Abs Does Not Operate Efficiently

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

Retrieve DTC. Go to appropriate DTC for diagnostic procedure. Check speed sensor circuit. See DTC 31-34 under SELF-DIAGNOSTICS . Check brakelight switch circuit. See DTC 49 under SELF-DIAGNOSTICS. Check ABS/TRAC actuator. See ABS/TRAC ACTUATOR CHECK under DIAGNOSIS & TESTING. If ABS/TRAC actuator is not okay, check hydraulic system for leakage. See Figure. If all preceding tests are okay, replace ABS/TRAC ECU.