Code No.U0019 Bus off (CAN-B)


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, always diagnose the CAN bus lines.
  • Before replacing the hands free-ECU, be sure to check that the power supply circuit, earth circuit, and communication circuit are normal.

TROUBLE JUDGMENT
When the hands free-ECU is returned from the bus off state, or when the bus error is indicated to the hands free-ECU state, the diagnosis code U0019 (CAN-B) is set.

COMMENTS ON TROUBLE SYMPTOM
The hands free-ECU, power supply for the hands free-ECU, earth circuit, or CAN bus line may have a problem.

PROBABLE CAUSES

  • Malfunctions of the hands free-ECU
  • Malfunction of CAN bus line wiring harness and connector

DIAGNOSIS PROCEDURE

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

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).

STEP 2. Check whether the M.U.T.-III can communicate with the hands free-ECU.

Q. Is the check result normal?
Erase the diagnosis code. This diagnosis is complete.
Check the power supply circuit of the hands free-ECU, and repair if necessary.