2022-2024 Audi A3, S3, RS 3 Third Brake Light Warning TSB

Symptoms

Owners of 2022-2024 Audi A3, S3, and RS 3 vehicles may observe "A warning for the third brake light is displayed in the instrument cluster", despite the lamp functioning normally. This warning might disappear after the ignition is cycled off and then back on. Technicians often confirm that the wiring for the third brake light is intact and the light itself operates correctly, yet the Audi A3 third brake light warning persists.

Fault Codes / DTCs

When diagnosing this issue, technicians will typically find the following Diagnostic Trouble Code (DTC) stored in the Electronic Central Electrical (BCM), specifically in the -J519- control unit (address word 0009):

Code	Description	Module
B12C615	Bulb for high-mount brake light open circuit/short circuit to B+ intermittent	Electronic Central Electrical (BCM) -J519-

Diagnosis / Trigger Conditions

The root cause of the Audi A3 third brake light warning and DTC B12C615 is identified as software sensitivity within the Electronic Central Electrical (BCM) -J519- module. This sensitivity leads to false warnings, indicating a problem that does not physically exist with the third brake light bulb or its wiring.

Repair Procedure Summary

Audi Technical Service Bulletin 2073316/1 outlines a two-pronged approach to resolve the false third brake light warning. The specific repair depends on the current software level of the Electronic Central Electrical (BCM) -J519-.

1. Software Level Check: The first step involves checking the software (SW) level of the BCM -J519- (address word 0009).
2. Software Update (for SW 0182 and lower): If the vehicle's BCM has software version 0182 or lower, technicians will update the BCM using the SVM action code 09A059. The update involves moving from old software versions (0174-0182) to a new version (0183 or higher). The relevant part number for this software is 5WA 937 089.
3. Suppression Capacitor Removal (for SW 0183 and higher): For vehicles with BCM software version 0183 or higher, the repair involves removing a suppression capacitor, C24. This capacitor is located near the yellow arrow on the right side of the luggage compartment. Technicians will remove the heat-shrink from around the capacitor, cut it from the wiring harness, and then insulate the exposed crimps using heat-shrink hose from the VAS 1978B wire harness repair set. Finally, the wiring harness is wrapped with fabric adhesive tape N 10592002.

This TSB 2073316/1 supersedes previous service solutions, including Pending Service Solution 2067742 and TSB 2071331/2.

Required Tools or Parts

To perform the necessary repairs, technicians may require the following items:

• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual (check ETKA).
• Cloth adhesive tape: Part number N 10592002.
• Wire harness repair set: Part number VAS 1978B.

Important Warnings

When performing SVM updates, technicians must always use DoIP (Diagnostic over Internet Protocol) in supported vehicles. To activate DoIP, navigate to Administration>>General>>GFF Process>>DoIP communication and select "Only allow DoIP communication." This setting will reset after the diagnostic session. A red LED on the VAS 6154(A) indicates active DoIP. Refer to TSB 2011732 for detailed SVM operating instructions.

Warranty Information

This repair is generally covered under Audi's new vehicle limited warranty, typically up to 48 months or 50,000 miles. For Certified Pre-Owned (CPO) vehicles, coverage falls under G10. If the vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance for diagnosis and repair.

NHTSA ID: 10251661