Inspection Procedure 1: M.U.T.-III cannot communicate with ETACS-ECU.
caution
Before replacing the ECU, ensure that the communication circuit is normal.
COMMENTS ON TROUBLE SYMPTOM
ETACS-ECU is communicating with M.U.T.-III via CAN. Therefore, communication error of ETACS-ECU is suspected.
PROBABLE CAUSES
Malfunction of the power supply and the earth of ETACS-ECU
Malfunction of CAN bus line
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use 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 the power supply circuit and the earth circuit to ETACS-ECU.
Refer to Inspection Procedure "ETACS-ECU power supply circuit"
.
Q. Is the check result normal?
Go to Step 3.
Repair the power supply circuit and the earth circuit to ETACS-ECU.
STEP 3. Retest the system
Check if M.U.T.-III can communicate with ETACS-ECU.
Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction
).
Replace ETACS-ECU and register the ID codes (Refer to
).