Code No.U1120 Failures Information on Engine-ECU (Related to Engine)


caution If diagnosis code U1120 is set in the multi display station, always diagnose the CAN bus lines.

TROUBLE JUDGMENT



COMMENTS ON TROUBLE SYMPTOM


Current trouble
  • The engine-ECU or the multi display station may be defective.
Past trouble
  • Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the multi display station and the engine-ECU. For diagnosis procedures, refer to "How to treat past trouble" (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points ).

POSSIBLE CAUSES



  • Damaged harness wires and connectors
  • Malfunction of engine-ECU
  • Malfunction of multi display station

DIAGNOSSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics



Q. Is the check result satisfactory?





STEP 2. M.U.T.-III other system diagnosis code



Q. Is the diagnosis code set?





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




    A/C-ECU

    • Code No.U1120: Failure information on engine-ECU (related to engine)

Q. Is the diagnosis code set?





STEP 4. Check whether the diagnosis code is reset.



(1)Replace the multi display station temporarily.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to "ON" position.
(4)Check if the diagnosis code is set.

Q. Is the check result satisfactory?





STEP 5. Check whether the diagnosis code is reset.



(1)Replace the engine-ECU temporarily.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to "ON" position.
(4)Check if the diagnosis code is set.

Q. Is the check result satisfactory?





STEP 6. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)Check if the diagnosis code is set.

Q. Is the check result satisfactory?