Code No. U1102 ASTC-ECU Time-out <Except vehicles for Morocco>


caution If Diagnosis Code U1102 is output from engine-ECU surely perform CAN bus line 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 set, 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 set. 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 second or more.

COMMENT ON TROUBLE SYMPTOM


Current malfunction
  • The failure is possibly caused by malfunction of the harness and connector in CAN bus line 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
  • Focus on diagnosing malfunction of the harness and connector in CAN bus line between engine-ECU and ASTC-ECU as well as malfunction in the power supply system of ASTC-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
    note In case of Past trouble, M.U.T.-III CAN bus diagnosis cannot detect the failure even if there is malfunction in CAN bus, so that check CAN bus line in the same way as Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ). The diagnosis codes being set to each ECU with CAN communication can narrow down the most suspected area. (Refer to GROUP 54C - Explanation About The M.U.T.-III Can Bus Diagnostics ).

PROBABLE CAUSE



  • 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 bus line diagnosis.

Q. Is the check result normal?
Go to Step 2.
Correct CAN bus line (Refer to GROUP 54C - Diagnosis - Can Bus Diagnostic Chart ), 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 set?
YES : Perform the troubleshooting of anti-skid braking system (Refer to GROUP 35B - Troubleshooting - Check 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

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

Q. Is the diagnosis code set?
Go to Step 4.
Intermittent malfunction in CAN bus line 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 set?
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 DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).
The check is end.