CODE NO. U1102 ASTC-ECU TIME-OUT <Vehicles with ASTC>


caution If Diagnosis Code U1102 is output from engine-ECU <M/T> or engine-A/T-ECU <A/T> surely perform CAN busline diagnosis.
caution Replace ECU after certainly confirming that the communication circuits are normal.
note When the diagnosis codes relating to the CAN communication error are output, make sure of the vehicle equipment. When the vehicle is not equipped with the system the engine-ECU communicates to, the diagnosis code is always output. This is not abnormal.

TROUBLE JUDGMENT


Check Conditions
  • While the cranking switch is in OFF position, or when 3 seconds pass after the cranking switch is in OFF from ON.
  • The battery voltage is 10V or more.
Judgment Criterion
  • The signals cannot be received from ASTC-ECU through CAN busline.

COMMENT ON TROUBLE SYMPTOM


Current malfunction
  • The failure is possibly caused by malfunction of the harness and connector in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> and ASTC-ECU, by malfunction in the power supply system of ASTC-ECU, in ASTC-ECU itself, in engine-ECU <M/T> or engine-A/T-ECU <A/T>.
Past malfunction
  • Proceed with troubleshooting focusing on malfunction of the harness and connector in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> 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-ECU <M/T> or engine-A/T-ECU <A/T>
  • Failed ASTC-ECU

DIAGNOSIS

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 GROUP 54D - Troubleshooting - CAN Bus Diagnostics 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. Is the diagnosis code output?
Perform the troubleshooting of ASTC (Refer to GROUP 35C - Troubleshooting - Diagnosis Code Chart ).
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. Transfer-ECU

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

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

  • Reconfirm whether the diagnosis code is output from engine-ECU <M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?
Replace the ASTC-ECU. Then go to Step 6 .
Intermittent malfunction in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> (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 code is output from engine-ECU <M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>. Then go to Step 6 .
Intermittent malfunction in CAN busline between engine-ECU <M/T> or engine-A/T-ECU <A/T> 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 code is output from engine-ECU <M/T> or engine-A/T-ECU <A/T>.

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

Q. Is the diagnosis code output?
Go to step 1 .
Check end.