2025-2026 Audi A5/S5/A6 Door Cannot Be Opened TSB

Owners of certain 2025-2026 Audi A5, S5, and A6 models may experience an issue where a door cannot be opened from the outside. Audi has released Technical Service Bulletin (TSB) 2079919/3 to address this condition, which can stem from a software or hardware problem within the door control unit or door lock.

This TSB, identified as transaction number 2079919/3, provides detailed diagnostic steps and repair procedures for technicians to resolve the problem, ensuring your Audi A6 door cannot be opened issue is properly fixed.

Symptoms

Owners typically report that "One of the doors cannot be opened intermittently from the outside. It can always be opened from the inside. All other doors can be opened from the outside." Additionally, the door might open again from the outside after the interior door handle of the affected door has been pulled out.

Fault Codes / DTCs

In some cases, a diagnostic trouble code (DTC) may be stored in the door control unit for the faulty door. The specific DTC associated with this issue is:

• B122D29 - "Lock unit for central locking - implausible signal - passive/intermittent"

Diagnosis and Trigger Conditions

If the Audi A6 door cannot be opened and DTC B122D29 is present, technicians are instructed to measure the resistance on the installed door lock between pin 2 and pin 4 using a multimeter. To do this, the door lock must first be put into temporary crash redundancy (TCR) mode by removing its connector and firmly pulling the interior door handle twice.

The expected resistance values are:

• Temporary crash redundancy (TCR) (without operating door handles): 1000 ohms
• Switch for interior door handle (IDH) + TCR (operating interior door handle only): 382 ohms

These measurements have a tolerance of +/- 1%. If the initial TCR measurement is not 1000 ohms, the interior door handle should be pulled twice again, and the measurement repeated. After closing and reopening the door, an open load (OL) should be measured instead of 1000 ohms.

If no DTC B122D29 is logged, the technician will check if the complaint occurs when the vehicle is unlocked. If it does, the door control unit is replaced. If not, the repair is postponed, and the vehicle may require a software update as per TSB 2079690.

Important Warnings

Audi explicitly states that if the complaint cannot be reproduced without a DTC, "In this case, replacing parts or attempting repairs will not fix the problem. Unjustified work/replacement parts will be charged back. Invoicing under warranty is not permitted." This means owners should ensure the issue is consistently reproducible before seeking repair if no fault code is present.

Repair Procedure Summary

For vehicles with DTC B122D29 and resistance values that deviate from specifications, the affected door lock should be replaced. If the resistance values are within specification, the door lock wiring should be checked using Guided Fault Finding. If the wiring is found to be acceptable, the door control unit for the faulty door should then be replaced.

If the Audi A6 door cannot be opened but no DTC B122D29 is present, and the issue occurs when the vehicle is unlocked, the door control unit is replaced. If the complaint cannot be reproduced, technicians are advised to check for and perform a combined software update described in TSB 2079690, specifically software version "03.10.00/C (28.13.01) KD2".

Required Tools or Parts

Technicians will require a multimeter for resistance measurements. Specific part numbers for replacement door locks or door control units will be determined during the diagnostic process.

Warranty Information

This Technical Service Bulletin is informational only if the vehicle is outside of any warranty. Warranty claims must adhere to the Audi Warranty Policies and Procedures Manual. Labor operations are assigned specific codes for billing purposes:

• Service Number 6438: Problem reproduced Without DTC B122D29 (Damage Code 0040 for lock/control unit replacement, KD02 for software update).
• Service Number 5717: Front Lock measure / replace.
• Service Number 5817: Rear Lock measure / replace.

Associated labor operations include removing and installing door trim (7059 1900, 7073 1900), checking/measuring door locks (5717 0299, 5817 0299, 5717 0499, 5817 0499), and replacing door locks (5717 1950, 5817 1950) or door control units (6438 1950). Software updates are covered under Service Number 6438 with Damage Code KD02, including labor operations like 0151 0010 and 0151 0040 (130 TU).

Owner Action

If you own a 2025-2026 Audi A5, S5, or A6 and experience a door that cannot be opened from the outside, contact your authorized Audi dealership. Describe the symptoms accurately, noting if the issue is intermittent or constant, and if any dashboard warnings appear. Referencing TSB 2079919/3 can help ensure your service center is aware of the latest diagnostic and repair procedures for this specific issue.

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Source: NHTSA ID: 11031022, Transaction No.: 2079919/3