Code No. U0100 Engine time-out error
Code No. U0121 ABS time-out error
Code No. U0141 ETACS time-out error



caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION



  • The signals from the engine-ECU, ABS-ECU <vehicles without ASC>, ASC-ECU <vehicles with ASC>, and ETACS-ECU are sent to the electric power steering-ECU.

FUNCTION



  • The signals from the engine-ECU, ABS-ECU <vehicles without ASC>, ASC-ECU <vehicles with ASC>, and ETACS-ECU are sent to the electric power steering-ECU for motor control.

TROUBLE JUDGEMENT


Check Conditions
  • The power supply circuit system diagnosis code (No. C1540, C1541) is not set.
  • The diagnosis code related to engine circuit system, ABS circuit system <vehicles without ASC>, ASC circuit system <vehicles with ASC>, and ETACS circuit system is set.
Judgement Criterion
  • The signal from the engine-ECU is not received for 55 seconds.
  • The signal from the ABS-ECU <vehicles without ASC>, ASC-ECU <vehicles with ASC>, and engine-ECU cannot be received for 11 seconds.
  • The signals from the engine-ECU, ABS-ECU <vehicles without ASC>, ASC-ECU <vehicles with ASC>, and ETACS-ECU are not sent, and the microcomputer determines that there is a problem in the system.
Fail Safe, Back Up Function
  • The electric power steering-ECU illuminates the electric power steering warning display, and sets the diagnosis code Nos. U0100, U0121, and U0141. However, the assist operation is limited only with the diagnosis code No. U0121.

PROBABLE CAUSES



  • Malfunction of CAN bus line
  • Malfunction of the electric power steering-ECU
  • Malfunction of the engine-ECU
  • Malfunction of the ETACS-ECU
  • Malfunction of the ABS-ECU <vehicles without ASC>
  • Malfunction of the ASC-ECU <vehicles with ASC>

DIAGNOSIS PROCEDURE


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


Use M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines


(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis codes U0100, U0121 or U0141 set?

Go to Step 3.
This diagnosis is complete.

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


Use M.U.T.-III to check if the same diagnosis code (time-out) is set in the other ECU (CAN-C).

Q. Is any diagnosis code set?

YES (Code No. U0100 is set) : Replace the engine ECU, and then go to Step 4.
YES (Code No. U0121 is set) : Replace the ABS-ECU <vehicles without ASC>, ASC-ECU <vehicles with ASC>, and then go to Step 4.
YES (Code No. U0141 is set) : Replace the ETACS-ECU, and then go to Step 4.
NO (No diagnosis code is set.) : Go to Step 4.

STEP 4. Check whether the diagnosis code is reset


(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis codes U0100, U0121 or U0141 set?

Replace the electric power steering-ECU (Refer to ).Then go to Step 5.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 5. Check whether the diagnosis code is reset


(1)Erase the diagnosis code.
(2)Turn the ignition switch from the LOCK (OFF) position to the ON position.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis codes U0100, U0121 or U0141 set?

Return to Step 1.
This diagnosis is complete.