2021 Audi e-tron Tail Light Warning DTCs B16D431, B16D531

Owners of the 2021 Audi e-tron may experience a "tail lamp warning displayed in the instrument cluster" or notice that the "turn signal indicator in the instrument cluster may flash rapidly when the turn signal is activated." These symptoms are typically linked to diagnostic trouble codes (DTCs) stored in the comfort system central control module, J393.

Important Warnings for High-Voltage Vehicles

Before any software update on vehicles with high-voltage components, it is crucial to follow specific safety procedures. To prevent damage to high-voltage components, the high-voltage cable must be removed before entering the SVM code. Charging the high-voltage battery during a software update can cause significant damage to these sensitive components.

Symptoms

If you own a 2021 Audi e-tron, you might observe the following issues:

• A "tail lamp warning displayed in the instrument cluster."
• The turn signal indicator in the instrument cluster flashing rapidly when the turn signal is activated.

These symptoms indicate a potential issue with the tail lamp system, specifically related to the diagnostic software.

Fault Codes / DTCs

When these symptoms occur, one or more of the following DTCs may be stored in the comfort system central control module, J393 (address word 0046):

| Code | Description | Module | | :--- | :---------- | | B16D431 | Left tail lamp 1, no signal/open circuit | J393 | | B16D631 | Right tail lamp 1, no signal/open circuit | J393 | | B16D531 | Left tail lamp 2, no signal/open circuit | J393 | | B16D731 | Right tail lamp 2, no signal/open circuit | J393 |

These codes specifically point to an open circuit or no signal condition for various tail lamp components.

Diagnosis and Trigger Conditions

The root cause of the 2021 Audi e-tron tail light warning B16D431 and related DTCs is identified as overly sensitive diagnostic software within the tail lamps. This sensitivity can lead to false error detections and trigger the warning messages and rapid turn signal flashing even when there isn't a physical fault with the lamps.

Repair Procedure Summary

The resolution for the 2021 Audi e-tron tail light warning B16D431 and associated issues involves a software update for the tail lamps. Technicians must follow these steps:

1. Refer to TSB 2011732 for detailed instructions on Software Version Management (SVM) operating procedures.
2. Update the tail lamps using the SVM action code 625A003. This update will install new software and hardware part numbers, which are listed in a specific table within the bulletin, ensuring the correct versions are applied.

Required Tools or Parts

To perform this software update, technicians will need the following specialized equipment:

• VAS 6160/VAS 6150: A VAS tester equipped with the current version of ODIS (Offboard Diagnostic Information System) running on Windows 10.

Warranty Information

This software update is covered under Audi's warranty program. Claims can be submitted for vehicles up to 48 months or 50,000 miles. For Certified Pre-Owned (CPO) vehicles, the G10 claim type applies, requiring owner verification. If the vehicle is outside of warranty, this Technical Service Bulletin serves as informational guidance only.

The service number for this operation is 9431, with a damage code of 0039. The labor operation for the software update, including checking for DTCs, is 0151 0000, with a maximum time allowance of 100 Technical Units (TU).

NHTSA ID: 10199220