2021-2024 Audi Q5/Q7/SQ5/SQ7 Taillight Switching Issue B146C29

Audi has released Technical Service Bulletin (TSB) 2070964/2 to address a functional issue with the taillights in the rear lid of several models. This TSB, dated April 11, 2024, supersedes a previous bulletin, 23-68, from November 17, 2023. It specifically applies to 2021-2024 Audi Q5, Q7, SQ5, and SQ7 vehicles.

The TSB details how foreign bodies can interfere with the rear lid sensor, leading to incorrect taillight operation. Owners experiencing the Audi Q7 taillight issue B146C29 should be aware of these potential causes and the recommended repair procedures.

Symptoms

Owners of affected Audi vehicles may observe the following symptoms related to their taillights:

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

Fault Codes / DTCs

When these symptoms occur, a diagnostic trouble code (DTC) may be stored in the comfort system central control module, identified as -J393- (address word 0046).

Code	Description	Module
B146C29	Rear Lid Closed Sensor Range/Performance	Comfort System Central Control Module (J393)

Technical Background

According to Audi, the root cause of the taillights not switching correctly is often the presence of foreign bodies. These obstructions can be located in the area of the rotary latch or the rear lid sensor, preventing proper detection of the rear lid's open or closed state.

Repair Procedure Summary

Addressing the Audi Q7 taillight issue B146C29 typically begins with a visual inspection and cleaning. Technicians should first visually inspect the rotary latch and the rear lid sensor area for any coarse dirt, stones, or other loose foreign bodies. Figures 1 and 2 in the TSB illustrate common areas where debris can interfere with the sensor's operation.

After identifying and carefully removing any obstructions, the technician must re-check the taillight functionality to ensure correct switching when the rear lid is opened and closed. If the issue persists after cleaning, the next step involves using diagnostic tools to access the convenience control unit (address word 0046, J393). Within this module, the measured value block should be checked to verify the proper functioning of the rear lid sensors. Any further repair work would be based on these diagnostic findings.

Important Warnings

Audi explicitly states that this type of damage is considered to be due to outside influence. Consequently, this issue is not covered by any standard Audi Warranty. Furthermore, claims for replaced parts will not be reimbursed if the issue is resolved by cleaning or is determined to be caused by external factors.

Owner Action

If you are experiencing the Audi Q7 taillight issue B146C29, or similar symptoms with your taillights not switching correctly or staying on, it is recommended to schedule a service appointment with an authorized Audi dealership. While the repair often involves a simple cleaning of the rear lid sensor and latch area, proper diagnosis using specialized tools may be necessary. Be aware that this type of repair, stemming from external debris, is generally not covered under Audi's standard warranty, and you may be responsible for the diagnostic and repair costs. Prompt attention to this issue can prevent further inconvenience and ensure your vehicle's lighting system functions as intended.

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Source: NHTSA ID: 10254077