If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, always diagnose the CAN bus lines.
DIAGNOSIS CODE SET CONDITIONS
If the CAN data from the ETACS-ECU cannot be received for 3 seconds or longer, the MCU will set the diagnosis code No. U1109.
PROBABLE CAUSES
The CAN bus line is defective.
Malfunction of the MCU
ETACS-ECU malfunction
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnosis
Use the M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting .) Then go to Step 2.
STEP 2. Diagnosis code recheck
Check again if the diagnosis code No. U1109 is set to the MCU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor switch from the LOCK (OFF) position to the ON position.
(3)Check if the diagnosis code is set.
Q.
Is the diagnosis code set?
Go to Step 3.
This diagnosis is complete.
STEP 3. M.U.T.-III Diagnosis code of other systems
Check if diagnosis code is set to the ETACS-ECU.
Q.
Is the diagnosis code set?
Carry out troubleshooting for the ETACS-ECU. (Refer to GROUP 54A - Troubleshooting .)
Go to Step 4.
STEP 4. M.U.T.-III Diagnosis code of other systems
Check if the diagnosis code No. U1109 is set to the combination meter.
Q.
Is the diagnosis code set?
Go to Step 5.
Go to Step 6.
STEP 5. Diagnosis code recheck
Check again if the diagnosis code is set to the MCU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor 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 ETACS-ECU.
A poor connection, open circuit of the wiring harness or other intermittent malfunction is present in the CAN bus line between the ETACS-ECU and MCU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Handle Intermittent Malfunction)
STEP 6. Diagnosis code recheck
Check again if the diagnosis code is set to the MCU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor 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 MCU.
A poor connection, open circuit of the wiring harness or other intermittent malfunction is present in the CAN bus line between the ETACS-ECU and MCU (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Handle Intermittent Malfunction)
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting 
.) Then go to Step 2.