Code No. U0120: GCU CAN timeout



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.

TROUBLE JUDGEMENT


The PHEV-ECU stores diagnosis code No. U0120 when it cannot communicate with the GCU via CAN correctly.

PROBABLE CAUSES



  • Malfunction of CAN bus
  • Malfunction of GCU
  • Malfunction of PHEV-ECU

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 3.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Go to Step 3.
The procedure is complete.

STEP 3. M.U.T.-III other system diagnosis code



  • Use M.U.T.-III to check whether the front GCU related diagnosis code is stored. (Refer to )

Q. Is the diagnosis code stored?

Troubleshoot for the relevant diagnosis code.
Go to Step 4.

STEP 4. Check whether the diagnosis code is stored.


Check if the diagnosis code No. U0120 is stored in the BMU.

Q. Is the diagnosis code stored?

Troubleshoot for the relevant diagnosis code. (Refer to ).
Go to Step 5.

STEP 5. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Replace the PHEV-ECU (Refer to ).
The procedure is complete.