DTC B1E18: Taillight (LH) deactivated (FET failure): Diagnosis

Using scan tool MB991958, read the ETACS-ECU diagnostic trouble code. 

Check if the DTC No. B16A8 is set to the ETACS-ECU.

Q: Is the DTC set? 

YES:  Carry out the troubleshooting for DTC No. B16A8. On completion, replace the ETACS-ECU when it has not been replaced as the troubleshooting process for DTC No. B16A8. This is because DTC No. B1E18 cannot be erased.

NO:  Replace the ETACS-ECU.