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Code No. U1104 SAS CAN timeout
 
 
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 - CAN Bus Diagnostics Table ).
  • If diagnostic trouble code U1104 is stored in ASC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect diagnostic trouble code may be stored. In this case, the stored diagnostic trouble code is not highly reliable.
  • When the steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
  • 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 ).
 
 
OPERATION
The ASC-ECU communicates with the steering wheel sensor via the CAN bus lines.
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITIONS
If the ACS-ECU cannot receive any signal from the steering wheel sensor for a predetermined period, this diagnostic trouble code will be stored.
 
 
PROBABLE CAUSES
  • The CAN bus line is defective.
  • Malfunction of the steering wheel sensor
  • 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 - Troubleshooting .) On completion, go to Step 2.
 
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Is diagnostic trouble code No. U1104 stored?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check other diagnostic trouble codes.
Check if diagnostic trouble code(s) other than U1104 is stored.
Is the diagnostic trouble code stored?
Perform troubleshooting for the relevant diagnostic trouble code. Then go to Step 5.
Go to Step 4.
 
STEP 4. Use scan tool MB991958 to confirm a diagnostic trouble code of other systems.
Check whether a steering wheel sensor "time-out" related diagnostic trouble code is stored in other ECUs.
Is the diagnostic trouble code stored?
Replace the steering wheel sensor. (Refer to .) Then go to Step 5.
Go to Step 5.
 
STEP 5. Check whether the diagnostic trouble code is stored again.
Check again if the diagnostic trouble code is stored.
(1) Erase the stored diagnostic trouble code.
(2) Ignition switch: LOCK (OFF)
(3) Ignition switch: ON
Is diagnostic trouble code No. U1104 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 ).