Inspection Procedure 11: ASC/ATC operate abnormally.


COMMENT ON TROUBLE SYMPTOM
Although the cause of the trouble cannot be clearly resolved since it depends on the running status and road surface condition, the ASC/ATC may operate abnormally due to malfunction of the vehicle speed sensor, G&yaw rate sensor, steering wheel sensor, and ASTC-ECU.

PROBABLE CAUSES

  • Too high or low tyre pressure
  • Tyre with the speed range less than specified
  • Varying tyre size
  • Tyres with different brands and different types
  • Tyres with different degrees of wear
  • Physically impossible uphill climbing
  • Malfunction of the wheel speed sensor
  • Steering wheel sensor malfunction
  • Neutral point dislocation of the steering wheel sensor
  • Malfunction of the G & yaw rate sensor
  • The ASTC-ECU is defective.

DIAGNOSIS

STEP 1. Check the tyre size.
Check if the tyres currently mounted to the 4 wheels are uniform and proper in size, brand, and type.

Q. Is the check result normal?
Go to Step 2.
Mount the specified size tyres to the 4 wheels. Then go to Step 8.

STEP 2. Check the tyre pressure.
Check if the pressure of tyres currently mounted to the 4 wheels is proper.

Q. Is the check result normal?
Go to Step 3.
Adjust the pressure to the proper value. Then go to Step 8.

STEP 3. Check for wheel speed sensor installation
Check the wheel speed sensor mounting bolt corresponding to the diagnosis code for looseness.

Q. Is the check result normal?
Go to Step 4.
Reinstall the wheel speed sensor correctly. Then go to Step 8.

STEP 4. Wheel speed sensor check
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the wheel speed sensor. Then go to Step 8.

STEP 5. Reinitialise the ASTC-ECU.
Refer to .

Q. Is the ASTC-ECU initialisation completed normally?
Go to Step 6.
Replace the ASTC-ECU, and initialise the ASTC-ECU again. Then go to Step 6.

STEP 6. Carry out the steering wheel sensor neutral point relearning.
Refer to .

Q. Is the neutral point relearning completed normally?
Go to Step 7.
Replace the steering wheel sensor, and carry out the neutral point relearning again. Then go to Step 8.

STEP 7. Carry out the G & yaw rate sensor neutral point relearning.
Refer to .

Q. Is the neutral point relearning completed normally?
Go to Step 8.
Replace the G & yaw rate sensor, and carry out the neutral point relearning again. Then go to Step 8.

STEP 8. Recheck the trouble symptom.

Q. Does ASC/ATC operate normally?
This diagnosis is complete.
Return to Step 1.