Code No.C1078: The diameter of different tyre wearing


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION


4WD-ECU receives the wheel speed data from ABS/ASC-ECU via the CAN communication.

DIAGNOSIS CODE SET CONDITION


Difference in rotation speed between the front and rear wheels exceeds continuously a specific value.

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 stored again.

Q. Is diagnosis code No.C1078 stored?
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 ABS diagnosis code (Refer to GROUP 35B - Troubleshooting ) <Vehicles with ABS> or the ASC diagnosis code (Refer to GROUP 35C - Troubleshooting ) <Vehicles with ASC>.

Q. Is the diagnosis code stored?
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 4WD-ECU. (Refer to ).