Code No.U1102: ABS-ECU or ASTC-ECU timeout


caution
  • If diagnosis code No.U1102 is set in the ETACS, diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.

TROUBLE JUDGEMENT



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 ABS-ECU or ASTC-ECU, the power supply circuits to the ABS-ECU or ASTC-ECU itself may be defective.
The M.U.T.-III shows a diagnosis code status as stored.
  • If diagnosis code No.U1102 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 ABS-ECU or ASTC-ECU, or power supply to the ABS-ECU or ASTC-ECU. 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 ABS-ECU or ASTC-ECU
  • 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 ABS-ECU or ASTC-ECU.



Q. Is the diagnosis code set?





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




  • Engine-ECU
    U1102: ABS-ECU or ASTC-ECU Timeout

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 diagnosis code set?





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 diagnosis code set?





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 diagnosis code set?