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TROUBLESHOOTING ACTIVE STABILITY & TRACTION CONTROL SYSTEM (ASTC) 35C-48 CAUTION • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior − CAN Bus Diagnostics Table .). • Before replacing the ECU, ensure that the communication circuit is normal. OPERATION • A toothed ABS rotor generates a pulse signal as it moves across the pickup field of each wheel • The wheel speed sensor transmit the frequency of the pulses to the ASTC-ECU. • The hydraulic unit assembly (integrated with ASTC-ECU) modulates the amount of braking DIAGNOSIS CODE SET CONDITION PROBABLE CAUSES Current trouble • Damaged wiring harness and connectors • Noise interference • Wheel speed sensor malfunction • ASTC-ECU malfunction Past trouble • Carry out diagnosis with particular emphasis on wiring harness and connector failures between − How to Cope with Intermit- tent Malfunctions .). DIAGNOSIS PROCEDURE STEP 1. M.U.T.-III CAN bus diagnosis Q: Is the check result normal? YES : Go to Step 3. NO : Repair the CAN bus lines (Refer to GROUP − CAN Bus Diagnostics Table .). On completion, go to Step 2. STEP 2. Diagnosis code recheck after resetting (2) Drive the vehicle at 15 km/h or more. NOTE: The ABS warning lamp does not turn OFF Q: Is the diagnosis code No.C1202 set? YES : Go to Step 3. NO : This diagnosis is complete. STEP 3. M.U.T.-III data list . • Item No.02: FR wheel speed sensor Q: Is the check result normal? YES : Go to Step 8. NO : Go to Step 4. STEP 4. Connector check: A-48 ASTC-ECU Q: Is the check result normal? YES : Go to Step 5. NO : Repair the defective connector. Then go to STEP 5. Voltage measurement at the A-48 ASTC- A-125 front wheel speed sensor (RH) connector. (2) Measure the voltage between the A-48 ASTC- ECU connector terminal No.6 and body earth. OK: 1 V or less Q: Is the check result normal? YES : Go to Step 6. NO : Repair the wiring harness. Then go to Step STEP 6. Resistance measurement at the A-48 the A-125 front wheel speed sensor (RH) (2) Measure the resistance between the A-48 ASTC- ECU connector terminal No.6 and body earth. OK: No continuity Q: Is the check result normal? YES : Go to Step 7. NO : Repair the wiring harness. Then go to Step |