Code No.U1101 Engine-A/T-ECU Time-out (Related to Automatic Transmission) <A/T>


caution
  • If diagnosis code U1101 is set in the combination meter, always diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.
note When the diagnosis codes relating to the CAN communication error are set, make sure of the vehicle equipment. When the vehicle is not equipped with the system the combination meter communicates to, the diagnosis code is always set. This is not abnormal.

TROUBLE JUDGMENT



note For M/T-vehicles, diagnosis code No.U1101 does not mean that there is a problem.

COMMENTS ON TROUBLE SYMPTOM


Current trouble
  • Connector(s) or wiring harness in the CAN bus lines between the engine-A/T-ECU and the combination meter, the power supply system to the engine-A/T-ECU, the engine-A/T-ECU itself, or the combination meter may be defective.
Past trouble
  • Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the engine-A/T-ECU and the combination meter, and the power supply system to the engine-A/T-ECU. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).
    note For a past trouble, you may not find it by the M.U.T.-III CAN bus diagnostics even if there is any failure in CAN bus lines. In this case, refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points . and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the diagnosis code, which is set regarding the CAN communication-linked ECUs (Refer to GROUP 54D - CAN Bus Line Diagnostic Flow ).

PROBABLE CAUSES



  • Damaged harness wires and connectors
  • Malfunction of engine-A/T-ECU
  • Malfunction of combination meter

DIAGNOSIS PROCEDURE


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



Q. Is the check result normal?





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




    ETACS-ECU

    • Code No.12: engine-A/T-ECU time-out (related to automatic transmission)

Q. Is the diagnosis code set?





STEP 4. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?





STEP 5. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?





STEP 6. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?