2021 Audi A4 Tail Lamp Warning TSB 2065234/2

Symptoms

Owners of 2021 Audi A4, S4, and A4 allroad vehicles may notice a "tail lamp warning displayed in the instrument cluster". Additionally, when the turn signal is activated, the indicator in the instrument cluster may flash more quickly than usual. These symptoms indicate a potential issue with the tail lamp system, often accompanied by stored diagnostic trouble codes.

Fault Codes / DTCs

When diagnosing the 2021 Audi A4 tail lamp warning, technicians may find several diagnostic trouble codes (DTCs) logged in the event memory of the convenience electronics (diagnostic address 0046), which is part of the comfort system central module. These codes point to various issues with the tail lamps:

Technical Background

The root cause of the 2021 Audi A4 tail lamp warning and associated DTCs is identified as overly sensitive diagnostic software within the vehicle's comfort module. This sensitivity leads to incorrect fault detection and logging, even when there may be no physical defect with the tail lamps.

Repair Procedure Summary

To address the 2021 Audi A4 tail lamp warning, a software update is required for the comfort system central control module, identified as J393 (address word 0046). The general procedure involves:

1. Initial Inspection: Before any software update, inspect the harness connection and the condition of the affected tail lamp(s). If any damage to the lamp, pins, connector, or wiring is found, these components must be repaired first, and the system reevaluated.
2. Software Update: If no damage is found, the comfort system central control module (J393) must be updated using the Software Version Management (SVM) system. This process requires following all instructions detailed in TSB 2011732: 00 Software Version Management (SVM), operating instructions.
3. SVM Action Code: The specific SVM action code to be used for this update is 625A004. This code is applied to Sub Address 0046 (tail lamp). The update will transition the software from older versions (e.g., 510 or 600) to newer versions (e.g., 710 or 700).
4. Reconfiguration: After the software update, various control units in the vehicle may need to be reconfigured to ensure proper function in conjunction with the updated comfort module.

Required Tools or Parts

Technicians will need specific equipment to perform this software update. The primary tool required is a VAS 6160/VAS 6150 tester running the current version of ODIS (Windows 10) diagnostic software.

Important Warnings

Owners should be aware of a critical warning regarding non-genuine components. If non-genuine retrofits or modifications (such as tuning) have been carried out on the vehicle and were not entered into the vehicle equipment list via feedback documentation, they may not function correctly after the software configuration process. Audi AG and the dealership will not accept liability for any damage caused by updating the software or failing to do so if such non-genuine components are present.

Source: NHTSA ID 11023744