Code No. C1078: Tyre Turning Malfunction


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.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION


AWC-ECU receives the wheel speed data from ASC-ECU via the CAN communication.

DIAGNOSIS CODE SET CONDITIONS


The wheel speed is observed when the vehicle is driven straight ahead with the steering angle in the neutral position and if the wheel speed difference which is more than the specified value is continuously detected, this code is set.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting). After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the diagnosis code is set again.

Q. Is diagnosis code No.C1078 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check the tyres
Check that the wheels/tyres with the identical size are installed, and that each tyre pressure is within the value specified on the tyre pressure label.

Q. Is the check result normal?
Go to Step 4.
Install the wheels/tyres with the identical size, or adjust the tyre pressure. Then go to Step 5.

STEP 4. M.U.T.-III other system diagnosis code.
Check the ASC diagnosis code (Refer to GROUP 35C - Troubleshooting ).

Q. Is the diagnosis code set?
Perform the relevant troubleshooting.
Go to Step 5.

STEP 5. M.U.T.-III data list.
Check the following data list. (Refer to ).

  • Item No.18: FL wheel speed sensor
  • Item No.19: FR wheel speed sensor
  • Item No.20: RL wheel speed sensor
  • Item No.21: RR wheel speed sensor

Q. Is the check result normal?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction).
Replace the AWC-ECU. (Refer to ).