Code No. U1102: ASTC-ECU time-out


caution If Diagnosis Code U1102 is output from engine-A/T-ECU surely perform CAN busline diagnosis.
caution Replace ECU after certainly confirming that the communication circuits are normal.

TROUBLE JUDGMENT


Check Conditions
  • While the cranking switch is in OFF, or when 3 seconds pass after the cranking switch is in OFF from ON.
  • Battery voltage is more than 10 V.
Judgment Criterion
  • The signal sent by ASTC-ECU through CAN busline is not received.

COMMENT ON TROUBLE SYMPTOM


Current malfunction
  • The failure is possibly caused by malfunction of the harness and connector in CAN busline between engine-A/T-ECU and ASTC-ECU, by malfunction in the power supply system of ASTC-ECU, in ASTC-ECU itself, in engine-A/T-ECU.
Past malfunction
  • Proceed with troubleshooting focusing on malfunction of the harness and connector in CAN busline between engine-A/T-ECU and ASTC-ECU and malfunction in the power supply system of ASTC-ECU. For diagnosis procedure, refer to how to cope with past malfunctions (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Treat Past Malfunctions ).
    note In the case of past malfunctions, M.U.T.-III CAN busline diagnosis cannot detect a malfunction even if there is a malfunction in CAN bus. Therefore, check CAN busline as in the case of response to intermittent malfunctions (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ). It is possible to narrow down areas with a high possibility of malfunctions from diagnosis codes output to each ECU that performs CAN communication (Refer to GROUP 54D - Explanation about the M.U.T.-III CAN Bus Diagnostics ).

PROBABLE CAUSES



  • Failed of the harness and the connector
  • Failed engine-A/T-ECU
  • Failed ASTC-ECU

DIAGNOSIS PROCEDURE

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

  • Using M.U.T.-III, perform CAN busline diagnosis.

Q. Is the check result normal?
Go to Step 2 .
Correct CAN busline (Refer to GROUP54D - Diagnosis - Can Bus Diagnosis Table ), and then go to Step 6 .

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

  • Confirm whether the diagnosis codes are output from ASTC-ECU.

Q. Are the diagnosis codes set?
Perform the troubleshooting of ASTC (Refer to GROUP 35C - Inspection Chart For Diagnosis Code ).
Go to Step 3 .

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

  • Confirm whether Diagnosis Code U1102: ASTC-ECU time-out is output from the following ECU having CAN communication with ASTC-ECU

  1. Combination meter

Q. Is the diagnosis code set?
Go to Step 4 .
Go to Step 5 .

STEP 4. M.U.T.-III diagnosis code

  • Reconfirm whether the diagnosis codes are output from engine-A/T-ECU.

  1. Erase the diagnosis codes being output.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis codes are output.

Q. Are the diagnosis codes set?
Replace the ASTC-ECU. Then go to Step 6 .
Intermittent malfunction in CAN busline between engine-A/T-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 5. M.U.T.-III diagnosis code

  • Reconfirm whether the diagnosis codes are output from engine-A/T-ECU.

  1. Erase the diagnosis codes being output.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis codes are output.

Q. Are the diagnosis codes set?
Replace the engine-A/T-ECU. Then go to Step 6 .
Intermittent malfunction in CAN busline between engine-A/T-ECU and ASTC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 6. M.U.T.-III diagnosis code

  • Reconfirm whether the diagnosis codes are output from engine-A/T-ECU.

  1. Erase the diagnosis codes being output.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis codes are output.

Q. Are the diagnosis codes set?
Go to step 1 .
Check end.