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DTC C1078: Tire Turning Malfunction
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect DTC 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.
 
 
DTC 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 DTC is set.
 
 
PROBABLE CAUSES
  • Tire with incorrect diameter equipped
  • Spare tire installed
  • Improper tire pressure
  • Malfunction of ASC-ECU
  • Malfunction of AWC-ECU

 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-IIISE) CAN bus diagnostics.
Use scan tool (M.U.T.-IIISE) to perform the CAN bus diagnosis.
Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Diagnosis, Can Bus Diagnostics Table ).
 
STEP 2. Check the tires
Check that the wheels/tires with the identical size are installed, and that each tire pressure is within the value specified on the tire pressure label.
Is the check result normal?
Go to Step 3.
Install the wheels/tires with the identical size, or adjust the tire pressure.
 
STEP 3. Scan tool (M.U.T.-IIISE) other system DTC.
Check the ASC DTC (Refer to GROUP 35C - Diagnosis, Diagnostic Trouble Code Chart ).
Is the DTC set?
Perform the relevant troubleshooting.
Go to Step 4.
 
STEP 4. Scan tool (M.U.T.-IIISE) data list.
Check the following data list (Refer to ).
  • Item No.35: Wheel speed (FL)
  • Item No.36: Wheel speed (FR)
  • Item No.37: Wheel speed (RL)
  • Item No.38: Wheel speed (RR)
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the AWC-ECU (Refer to ).