Code No.U1100: Engine-ECU Time-out (Related to Engine)
Code No.U1101: A/T-ECU Time-out (Related to A/T)


caution
  • If diagnosis code No.U1100 or U1101 is set in the ETACS, diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.
  • For M/T-vehicles, diagnosis code No. U1101 does not mean that there is a problem..

TROUBLE JUDGMENT


Diagnosis code No.U1100
  • The ETACS-ECU receives engine control system-related signals from the engine-ECU through the CAN bus lines. If the ECU cannot receive the engine control system-related signal at all, diagnosis code No.U1100 will be set.
Diagnosis code No.U1101
  • The ETACS-ECU receives the transmission control signals from the A/T-ECU <A/T> via CAN bus lines. If the ECU cannot receive the transmission control signal at all, diagnosis code No.U1101 will be set.

COMMENT ON TROUBLE SYMPTOM


The M.U.T.-III shows a diagnosis code status as active.
  • Connector(s) or wiring harness in the CAN bus lines between the ETACS-ECU and the engine-ECU or the A/T-ECU <A/T>, the power supply circuits to the engine-ECU or the A/T-ECU <A/T> itself may be defective.
The M.U.T.-III shows a diagnosis code status as stored.
  • If diagnosis code No.U1100 or U1101 is set as past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) in the CAN bus lines between the ETACS-ECU and the engine-ECU or the A/T-ECU <A/T>, or power supply to the engine-ECU or the A/T-ECU <A/T>. For diagnosis procedures, refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Treat Past Trouble .
    note For a past trouble, you cannot 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 - How to Cope with Intermittent Malfunctions and check the CAN bus lines. You can narrow down the probable cause of the trouble by referring to the diagnosis code, which is set regarding the CAN communication-linked ECUs (Refer to GROUP 54C - CAN Bus Line Diagnostic Flow ).

PROBABLE CAUSES



  • Malfunction of the engine-ECU or the A/T-ECU <A/T>
  • Malfunction of the CAN bus

DIAGNOSIS PROCEDURE


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



Q. Is the check result normal?





STEP 2. Check the diagnosis code of the engine-ECU or the A/T-ECU <A/T>.



Q. Is the diagnosis code set?





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




  • ABS-ECU
    U1100: Engine-ECU time-out or U1101: A/T-ECU time-out <A/T>

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 from "LOCK" (OFF) position to "ON" position.
(3)On completion, check that the diagnosis code is reset.

Q. Is the check result normal?





STEP 5. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)On completion, check that the diagnosis code is reset.

Q. Is the check result normal?





STEP 6. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)On completion, check that the diagnosis code is reset.

Q. Is the check result normal?