2021-2025 Audi Q Series Taillight Malfunction B146C29

Audi has issued Technical Service Bulletin (TSB) 2070964/1, dated November 17, 2023, to address a functional issue with the switching of lights in the rear lid for various 2021-2025 Audi Q Series models. This bulletin specifically targets instances where owners experience an Audi Q Series taillight malfunction B146C29, indicating a problem with the rear lid sensor's performance.

The TSB applies to 2017-2024 Audi Q7, 2018-2025 Audi Q5 and SQ5, 2020-2025 Audi Q5 e quattro, 2020-2024 Audi SQ7, 2021-2025 Audi Q5 Sportback, and 2021-2025 Audi SQ5 Sportback vehicles. The primary cause of this Audi Q Series taillight malfunction B146C29 is often external factors affecting the rear lid's components.

Symptoms of Taillight Malfunction

Owners may notice specific issues related to their vehicle's taillights. These include:

• "The taillights do not switch correctly when the rear lid is opened or closed."
• "The taillights in the bumper light up constantly."

These symptoms suggest a problem with the vehicle's ability to accurately detect the rear lid's position, leading to incorrect taillight behavior.

Associated Fault Codes

When diagnosing this issue, technicians may find a specific Diagnostic Trouble Code (DTC) stored in the comfort system central control module, identified as -J393- (address word 0046). The relevant DTC is:

• DTC B146C29: Rear Lid Closed Sensor Range/Performance

This code directly points to a problem with the sensor responsible for detecting whether the rear lid is open or closed.

Understanding the Cause

According to Audi's technical background, the Audi Q Series taillight malfunction B146C29 occurs because the taillights do not switch correctly due to foreign bodies. These foreign bodies, such as coarse dirt, stones, or other loose debris, interfere with the proper operation of the rotary latch or the rear lid sensor itself.

Repair Procedure Overview

The recommended service procedure focuses on inspecting and clearing the affected area. There is no specific production solution for this issue, as it is typically caused by external factors.

1. Inspect for Debris: Technicians should first check the area around the rotary latch for any coarse dirt, stones, or other foreign bodies that might be obstructing its movement or the sensor. Figures 1 and 2 in the TSB illustrate examples of dirt and debris interfering with the rear lid sensor's operation.
2. Remove Obstructions: Any identified coarse dirt or foreign bodies must be carefully removed from the latch area and the rear lid sensor. After removal, the technician should verify if the taillights now switch correctly.
3. Further Diagnostics (if needed): If the issue persists after clearing debris, the technician should access the measured value block within the convenience control unit (diagnostic address 0046). This allows them to check if the sensors are functioning properly and to perform any additional necessary repair work.

Important Warranty Information

Audi explicitly states that this type of damage is considered to be due to outside influence. As a result, it is not covered by any Audi Warranty. Furthermore, claims for replaced parts related to this specific issue will not be reimbursed.

---

Source: NHTSA ID: 10246201