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DTC C1781 SAS internal fail
 
 
caution
  • 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 ).
 
 
OPERATION
FCM/LDW/AHB-ECU communicates with the steering wheel sensor via the CAN bus lines.
 
 
DTC SET CONDITION
This DTC is set when the abnormality below is detected:
  • The ECU receives a signal which indicates an internal error in the steering wheel sensor.
 
 
TROUBLESHOOTING HINTS
  • The steering wheel sensor has not been calibrated correctly.
  • Malfunction of the steering wheel sensor (column switch assembly)
  • Malfunction of the FCM/LDW/AHB-ECU
 
 
DIAGNOSIS
STEP 1. Check whether the steering wheel sensor is installed properly.
Is the check result normal?
Go to Step 2.
Install the steering wheel sensor properly.
 
STEP 2. Scan tool (M.U.T.-IIISE) data list.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Check the input signal (Refer to ).
  • Vehicle stopped (the steering wheel is in the neutral position)
 
Item No.Item nameNormal condition
17Steering wheel angle-6 to 6 deg
  • Vehicle is running.
 
Item No.Item nameNormal condition
17Steering wheel angleNearly the same as the steering wheel operation angle (-750 to 750 deg)
OK: Normal condition is displayed.
Is the check result normal?
Go to Step 3.
Replace the steering wheel sensor (column switch assembly) (Refer to GROUP 54A - Column Switch ).
 
STEP 3. Check whether the DTC is set again.
Check again if the DTC is set in the FCM/LDW/AHB-ECU.
(1) Erase the DTC.
(2) Turn off the power supply mode of the electric motor switch.
(3) Turn on the power supply mode of the electric motor switch.
(4) Check if DTC is set.
Is the DTC set?
Replace the FCM/LDW/AHB-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).