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Code No. C1394 INCOMP.learn neutral(SAS)
 
 
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, Trouble code diagnosis ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to and ).
  • When the steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
 
 
OPERATION
The steering wheel sensor output signal is sent to ASC-ECU via the CAN bus lines.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITIONS
ASC-ECU receives the information of the steering wheel sensor calibration from the steering wheel sensor. When this information indicates that the calibration is not performed, the ECU stores the diagnostic trouble code.
 
 
PROBABLE CAUSES
  • The CAN bus line is defective.
  • Steering wheel sensor calibration not implemented
  • Malfunction of ASC-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use the scan tool MB991958 to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - CAN Bus Trouble Symptom Chart .) On completion, go to Step 2.
 
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Is diagnostic trouble code No. C1394 stored?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Steering wheel sensor calibration
Perform calibration of steering wheel sensor. (Refer to .)
Is the check result normal?
Go to Step 4.
After the steering wheel sensor is replaced (Refer to ), calibrate the sensor (Refer to ). Then go to Step 4.
 
STEP 4. Check whether the diagnostic trouble code is stored again.
Check again if the diagnostic trouble code is set.
(1) Erase the stored diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF)
(3) Ignition switch: "ON"
Is diagnostic trouble code No. C1394 stored?
Replace the hydraulic unit (integrated with ASC-ECU). (Refer to .)
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).