If diagnosis code No.U1073 is set in the ETACS-ECU, diagnose the CAN bus (CAN-C-Mid) lines.
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 .)
TROUBLE JUDGMENT
If the ETACS-ECU detects a bus off error (CAN-C-Mid), diagnosis code No. U1073 will be set.
COMMENTS ON TROUBLE SYMPTOM
The ETACS-ECU or its CAN bus (CAN-C-Mid) lines may be defective.
PROBABLE CAUSES
Malfunction of the ETACS-ECU
Malfunction of wiring harness or connector
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 3.
STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)On completion, check that the diagnosis code is reset.
Q.
Is the diagnosis code set?
Refer to GROUP 54C, Diagnosis Item 5 "Communication with no ECUs is possible (CAN-C-Mid)" , and Then go to Step 3.
If the trouble is solved, it is determined that there is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points -
How to Cope with Intermittent Malfunctions ).
STEP 3. Check whether the diagnosis code is reset.
Recheck if the diagnosis code is set to the ETACS-ECU.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
.)
