Code No.U0100 Engine CAN timeout

caution

If diagnosis code No. U0100 is set, be sure to diagnose the CAN bus line.
When replacing the ECU, always check that the communication circuit is normal.

OPERATION

The clearance warning control unit sets diagnosis code No.U0100 when it cannot receive signals from the engine-ECU.

TROUBLE JUDGEMENT

If the communication with engine-ECU cannot be established for 2500 ms or more.

PROBABLE CAUSES

Malfunction of CAN bas line
Malfunction of engine-ECU power supply circuit
Malfunction of engine-ECU
Malfunction of clearance warning control unit

DIAGNOSIS PROCEDURE

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

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

Q. Is the check result normal?

Go to Step 2.

Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting

STEP 2. Check the M.U.T.-III Diagnosis code for other system.

Check if diagnosis code No. U0100 is set in the ETACS-ECU.

Q. Is the diagnosis code set?

Go to Step 3.

Go to Step 4.

STEP 3. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set in the clearance warning control unit.

(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 code set?

Replace the engine-ECU.

A poor connection, open circuit, or other intermittent malfunction in the CAN bus line between the clearance warning control unit and the engine-ECU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).

STEP 4. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set in the clearance warning control unit.

(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 code set?

Replace the clearance warning control unit (Refer to