Code No. U1102 ASTC-ECU Time-out


caution If Diagnosis Code U1102 is output from engine-ECU 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 Condition
  • The diagnosis code setting enabled signal is received from ETACS-ECU.
Judgment Criterion
  • The signals cannot be received from ASTC-ECU for 65 seconds or more.

COMMENT ON TROUBLE SYMPTOM


Current malfunction
  • The failure is possibly caused by malfunction of the harness and connector in CAN busline between engine-ECU and ASTC-ECU, by malfunction in the power supply system of ASTC-ECU, in ASTC-ECU itself, in engine-ECU.
Past malfunction
  • Proceed with troubleshooting focusing on malfunction of the harness and connector in CAN busline between engine-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-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 GROUP 54D - Troubleshooting - Can Bus Diagnostics Table ), and then go to Step 4 .

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 system (Refer to GROUP 35C - Troubleshooting - Inspection Chart for Diagnosis Code ).
Go to Step 3 .

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

  • Reconfirm whether the diagnosis codes are output from engine-ECU

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

Q. Is the diagnosis code output?
Go to Step 4 .
Intermittent malfunction in CAN busline between engine-ECU and ASTC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 4. Replace the ASTC-ECU

  • After replacing the ASTC-ECU, re-check the diagnosis code output.

Q. Is the diagnosis code output?
Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ). After registering the injector identification code, the vehicle equipped with the closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
The check is end.