Code No. U1102: ABS-ECU time-out <Vehicles without 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 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 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 ABS-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 ABS-ECU, by malfunction in the power supply system of ABS-ECU, in ABS-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 ABS-ECU and malfunction in the power supply system of ABS-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 ABS-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 ABS-ECU.

Q. Is the diagnosis code set?
Perform the troubleshooting of ABS (Refer to GROUP 35B - Troubleshooting - Diagnosis Code Chart).
Go to Step 3.

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

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

  1. Transfer-ECU

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 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 set.

Q. Is the diagnosis code set?
Replace the ABS-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 set.
  2. Ignition switch: "LOCK" (OFF) to ON
  3. Confirm whether the diagnosis code is set.

Q. Is the diagnosis code set?
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 ABS-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 set.

Q. Is the diagnosis code set?
Go to Step 1.
Check end.