If diagnosis
code No. U0019 is set, be sure to diagnose the CAN bus line.
When replacing the ECU, always check that the communication circuit is normal.
DIAGNOSIS FUNCTION
If a malfunction of the CAN-B circuit occurs, KOS-ECU sets the diagnosis code No. U0019.
JUDGEMENT CRITERIA
If KOS-ECU cannot perform the data transmission in normal conditions due to a malfunction
of the CAN-B bus circuit, KOS-ECU determines that there is a problem.
PROBABLE CAUSES
Malfunction of CAN bus line
DIAGNOSIS PROCEDURE
STEP 1. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
(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?
Go to Step 2.
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points ).
STEP 2. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points ).
Repair the CAN bus line (Refer to GROUP 54C -
Troubleshooting ).
Intermittent malfunction is suspected (Refer to GROUP 00 -
How to Use Troubleshooting/Inspection
Service Points 
).