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DTC U0431: ETACS Data Error


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

OPERATION


AWC-ECU communicates with the ETACS-ECU via the CAN bus lines.

DTC SET CONDITIONS


The code is set when abnormality is detected in the signal received from the ETACS-ECU.

PROBABLE CAUSES



DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting ).

STEP 2. Scan tool diagnostic trouble code
Check the ETACS diagnostic trouble code. (Refer to GROUP 54A - Troubleshooting ).

Q. Is the DTC set?
Perform the relevant troubleshooting.
Go to Step 3.

STEP 3. Scan tool data list
Check the following data list. (Refer to data list reference table ).

  • Item No. 39: Stoplight switch
  • Item No.43: Battery positive voltage

Q. Is the check result normal?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Go to Step 4.

STEP 4. Check whether the DTC is reset.

Q. Is DTC No. U0431 set?
Replace the AWC-ECU. (Refer to ). Then go to Step 5.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 5. Check whether the DTC is reset.

Q. Is DTC No. U0431 set?
Return to Step 1.
This diagnosis is complete.