Code No. C1011: FL wheel speed sensor signal Code No. C101C: FR wheel speed sensor signal Code No. C1027: RL wheel speed sensor signal Code No. C1032: RR wheel speed sensor signal
caution
If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).
OPERATION
A toothed rotor (for wheel speed detection) generates a voltage pulse as it moves across the pickup field of each wheel speed sensor.
The wheel speed sensor transmit the frequency of the pulses to the ASTC-ECU.
DIAGNOSIS CODE SET CONDITIONS
ASTC-ECU monitors the signals from each wheel speed sensor while the vehicle is being driven. If any fault below is found in these sensor signals, ASTC-ECU will set the relevant diagnosis code.
Irregular change in the wheel speed sensor signal
PROBABLE CAUSES
Current trouble
External noise interference
Damaged wiring harness and connectors
Malfunction of wheel speed sensor
Adhesion of foreign materials on the wheel speed sensor
Adhesion of foreign materials on the rotor (for wheel speed detection)
Improper installation of the wheel speed sensor
Malfunction of the hydraulic unit assembly (integrated with ASTC-ECU)
Deformation of the rotor (for wheel speed detection)
The number of poles on the rotor (for wheel speed detection) is changed
Past trouble
Carry out diagnosis with particular emphasis on wiring harness and connector failures between ASTC-ECU and the wheel speed sensor. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Cope with Intermittent Malfunctions ).
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnosis
Use M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 3.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.
STEP 2. Diagnosis code recheck after resetting CAN bus lines
Q.
Is diagnosis code No. C101C, C1011, C1032 or C1027 set?