TRAC System Does Not Operate
CAUTION:
If ABS/TRAC ECU replacement is instructed in following testing, always ensure ABS/TRAC ECU connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ABS/TRAC ECU malfunction.
Ensure no DTCs are present. See RETRIEVING DIAGNOSTIC TROUBLE CODES under DIAGNOSIS & TESTING. Inspect IG power supply circuit. See DTC 41: IG POWER SUPPLY CIRCUIT in ANTI-LOCK - SC300 & SC400 - WITH TRACTION CONTROL article. Inspect hydraulic lines for leakage. Repair as needed. Inspect speed sensor circuit(s). See DTC 31-34: SPEED SENSOR CIRCUIT in ANTI-LOCK - SC300 & SC400 - WITH TRACTION CONTROL article. If all preceding tests are okay, replace ABS/TRAC ECU.