Code No. U1200 SAS parity error
Code No. U1204 SAS message counter error


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the steering wheel sensor is replaced, always carry out calibration to make ASC-ECU learn the neutral point (Refer to ).
  • 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 steering wheel sensor signal is sent to the ASC-ECU via the CAN bus lines.

DIAGNOSIS CODE SET CONDITIONS


If a problem is found in the steering wheel sensor, the sensor will send a diagnostic signal to the ASC-ECU. When ASC-ECU receives this diagnostic signal, it determines that the sensor has a trouble and stores the diagnosis code.
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 line (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. U1200 or U1204 stored?
Go to Step 3.
This diagnosis is complete.

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

Q. Is diagnosis code No. U1200 or U1204 stored?
Replace the steering wheel sensor (Refer to ). Then go to Step 4.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 4. Check whether the diagnosis code is stored again.
Check again if the diagnosis code is stored.
(1)Erase the stored diagnosis code.
(2)Ignition switch: "LOCK" (OFF)
(3)Ignition switch: "ON"

Q. Is diagnosis code No. U1200 or U1204 stored?
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 5.
This diagnosis is complete.

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

Q. Is diagnosis code No. U1200 or U1204 stored?
Return to Step 3.
This diagnosis is complete.