Before
replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication
circuit are normal.
When the ETACS-ECU of vehicles without KOS is replaced, the encrypted code of the ignition
key needs to be registered to the ETACS-ECU. (If the encrypted code is not registered, the engine
cannot be started. Register the encrypted code as described in Immobilizer System - How
to Register Key ID .)
JUDGEMENT CRITERIA
ETACS-ECU sends the diagnosis code (U code) detection permission or prohibition signal
to each ECU connected to the CAN bus line. If the combination meter cannot receive the diagnosis code
(U code) detection permission or prohibition signal for 5 seconds after turning the electric
motor switch to ON position, diagnosis code U1190 will be set.
PROBABLE CAUSES
Malfunction of the ETACS-ECU
Malfunction of CAN bus line
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 ).
On completion, go to Step 6.
STEP 2. M.U.T.-III other system diagnosis code
Check if diagnosis code is set to the ETACS-ECU.
Q.
Is the diagnosis code set?
Diagnose the ETACS-ECU (Refer to ).
Go to Step 3
STEP 3. M.U.T.-III other system diagnosis code
Check if a diagnosis code, which relates to CAN communication-linked systems below, is
set.
KOS-ECU
Code No.U1190: No receive fault detect signal
Q.
Is the diagnosis code set?
Go to Step 4.
Go to Step 5.
STEP 4. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.
Q.
Is the diagnosis code set?
Replace ETACS-ECU and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in
the CAN bus lines between the ETACS-ECU and the combination meter (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points ).
STEP 5. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.
Q.
Is the diagnosis code set?
Replace combination meter and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in
the CAN bus lines between the ETACS-ECU and the combination meter (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points ).
STEP 6. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)On completion, check that the diagnosis code is not reset.
Go to Step 2
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting 
).
On completion, go to Step 6.