Code No. U1104: SAS CAN timeout


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 (Refer to GROUP 54C - Troubleshooting ).
  • If diagnosis code U1104 is set in ASTC-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect diagnosis code may be set. In this case, the set diagnosis code is not highly reliable.
  • When the steering wheel sensor is replaced, always carry out calibration to make ASTC-ECU learn the neutral point (Refer to ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).

OPERATION


The steering wheel sensor outputs the steering wheel status to ASTC-ECU via the CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS


If the ASTC-ECU cannot receive any signal from the steering wheel sensor for a predetermined period, this diagnosis code will be set.
PROBABLE CAUSES

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is diagnosis code No. U1104 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check other diagnosis codes.
Check if diagnosis code(s) other than U1104 is set.

Q. Is the diagnosis code set?
Perform troubleshooting for the relevant diagnosis code. Then go to Step 5.
Go to Step 4.

STEP 4. Use M.U.T.-III to confirm a diagnosis code of other systems.
Check whether a steering wheel sensor "time-out" related diagnosis code is set in other ECUs.

Q. Is the diagnosis code set?
Replace the column switch assembly (Integrated with steering wheel sensor) (Refer to GROUP 54A - Column Switch ). Then go to Step 5.
Go to Step 5.

STEP 5. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set.
(1)Erase the set diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"

Q. Is diagnosis code No. U1104 set?
Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).