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.

OPERATION

    Signals from the ECUs communicate with the EPS-ECU.

FUNCTION

    The signals from the ECUs communicate with the EPS-ECU for motor control.

TROUBLE JUDGEMENT
Check Conditions
    IG1 voltage: 10 V or more
Judgement Criterion
    The signals from the ECUs cannot communicate (bus off), and the microcomputer determines that there is a problem in the system.
Fail Safe, Back Up Function
    The EPS-ECU illuminates the electric power steering warning display, and sets the diagnosis code No. U0001 to limit assist operation.

PROBABLE CAUSES

  • Malfunction of CAN bus line
  • Malfunction of the EPS-ECU
  • Malfunction of the engine-ECU
  • Malfunction of the ETACS-ECU
  • Malfunction of the ABS-ECU <vehicles with ABS>
  • Malfunction of the ASC-ECU <vehicles with ASC>