2025 Audi A5 Footwell Moisture and Musty Smell TSB

Symptoms of Footwell Moisture and Musty Smell

Owners of the 2025 Audi A5 and A6 may experience several unpleasant symptoms related to moisture in the passenger compartment. The primary complaints include a persistent "musty or damp smell in the passenger compartment," often described as an "annoying odor," which can be noticeable in various areas such as the headliner, instrument panel, and especially the footwell. This odor is typically a strong indicator of moisture accumulation and potential mold or mildew growth within the vehicle's interior.

Beyond the smell, a more direct symptom is a "wet footwell in the front of the vehicle." Owners might discover the carpet in the front of the vehicle is damp or saturated with water. This "water entering" the footwell can lead to significant discomfort, potential damage to interior components, and a general decline in the vehicle's cabin air quality. If you detect any of these signs in your 2025 Audi A5 or A6, it's crucial to address the issue promptly to prevent further complications.

Technical Background of the Issue

The root cause of the Audi A5 footwell moisture and associated musty smell is often linked to the air conditioning system. Specifically, condensation generated by the air conditioning unit can enter the passenger compartment if the drain hose is not installed correctly. This misinstallation prevents the condensation from properly exiting the vehicle, causing it to accumulate inside. Over time, this trapped moisture saturates the carpet in the footwell, creating an ideal environment for musty odors to develop.

This issue is not related to a manufacturing defect in the AC unit itself but rather an installation anomaly of the drain hose. Audi Technical Service Bulletin (TSB) 2079787/1 identifies this specific problem and provides guidance for its resolution. The bulletin clarifies that there is no production solution required, meaning the issue is addressed through a service procedure rather than a change in the manufacturing process for new vehicles.

Repair Procedure Summary

The repair for the Audi A5 footwell moisture problem primarily involves inspecting and correcting the position of the air conditioning drain hose. Technicians will need to access the area where the drain hose connects to the AC unit to ensure it is properly routed and secured. The TSB provides a visual aid, Figure 1, titled "Assembly overview for the Audi A5 and A6," which illustrates the correct positioning of the drain hose.

Technicians are instructed to check the current position of the drain hose and adjust it as necessary to prevent condensation from leaking into the passenger compartment. This procedure ensures that the drain hose effectively channels water out of the vehicle, resolving the issue of a wet footwell and eliminating the source of the musty smell. The TSB does not specify any special tools or replacement parts for this repair, focusing instead on the correct installation of the existing component.

Required Documentation for Repair Claims

When submitting a warranty claim for this repair, Audi requires specific photographic documentation to be attached to DOC-IT. This ensures a clear reference to the vehicle and the complaint. The image or video documentation must:

• Include the vehicle's VIN and the date.
• Not be edited or altered in any way.
• Be in focus and taken with sufficient light; a high resolution is not strictly necessary.

Additionally, if appropriate, technicians should mark the exact location of the problem in the photo documentation. This helps parts analysis teams accurately reference the complaint. It is crucial to ensure that the photo documentation does not show any people, faces, license plates, or customer data to maintain privacy.

Warranty Information

This Technical Service Bulletin (TSB) 2079787/1 outlines the warranty claim process for addressing the footwell moisture and musty smell issue. The relevant details for service centers include:

• Service Number: 8791
• Damage Code: 0018
• Labor Operations:
  • Repair water drain hose – One side: Labor Operation 8791 4199, with an estimated time unit (TU) of 40.
  • Repair water drain hose – Both sides: Labor Operation 8791 4299, with an estimated time unit (TU) of 60.

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review or audit by Audi Warranty. Service centers are also advised to bill for any necessary drying or cleaning of the vehicle according to the time required to complete these tasks.

Important Notes for Owners

Owners should be aware that if their 2025 Audi A5 or A6 vehicle is outside of its warranty period, this Technical Service Bulletin 2079787/1 serves as informational guidance only. In such cases, the cost of diagnosis and repair may not be covered by Audi. It is always recommended to consult with an authorized Audi service center to determine your vehicle's specific warranty coverage and potential costs.

Source: NHTSA ID: 10250917