Code No. U0001: Bus-off


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 - 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 ASTC-ECU learn the neutral point (Refer to ).

OPERATION


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

DIAGNOSIS CODE SET CONDITIONS


When the system detects a malfunction in the CAN-bus line.

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 - CAN Bus Diagnostics Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

Q. Is diagnosis code No. U0001 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check whether the diagnosis code is set again.
Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "LOCK" (OFF) position.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the diagnosis code is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U0001 set?
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 set again.
Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "LOCK" (OFF) position.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the diagnosis code is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. U0001 set?
Return to Step 1.
The procedure is complete.