Code No. C1781: SAS Failure



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.
  • When the steering wheel sensor is replaced, calibrate the steering wheel sensor (Refer to GROUP 35C - On-vehicle Service )).

OPERATION




DIAGNOSIS CODE SET CONDITION




  • Abnormality in steering wheel sensor signal
  • The steering wheel sensor has not learned the neutral position yet.

PROBABLE CAUSES



  • Malfunction of the CAN bus line
  • Neutral position of steering wheel sensor not learned
  • Malfunction of the steering wheel sensor
  • Malfunction of ACC/FCM-ECU

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 2
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).

STEP 2. 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 3

STEP 3. Steering wheel sensor calibration


Perform calibration of steering wheel sensor (Refer to GROUP 35C - Steering Wheel Sensor Calibration ).

Q. Has the calibration succeeded?

Go to Step 4
Replace the steering wheel sensor (Refer to GROUP 35C - Steering Wheel Sensor ).

STEP 4. Check whether the diagnosis code is reset.


Q. Is diagnosis code No.C1781 set?

Go to Step 5
This diagnosis is complete.

STEP 5. M.U.T.-III data list.


Check the following data list (Refer to ).

  • Item No.40: Steering angle sensor
  • Item No.57: Steering angle sensor state

Q. Is the check result normal?

Go to Step 6
Replace the steering wheel sensor (Refer to GROUP 35C - Steering Wheel Sensor ).

STEP 6. Check whether the diagnosis code is reset.


Q. Is diagnosis code No.C1781 set?

Replace the ACC/FCM-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).