2025 Audi A5 AC System Malfunction TSB 2079225/1

Audi has issued Technical Service Bulletin (TSB) 2079225/1, also referred to as 87 PSS, to address an air conditioning system malfunction in certain 2025 Audi A5 and S5 vehicles. This issue causes the AC button to automatically deactivate immediately after being pressed, leading to a non-functional AC system. This TSB provides guidance for technicians and informs owners about the expected timeline for a permanent fix.

This particular Audi A5 AC malfunction is linked to a software issue within the vehicle's thermal management system.

Symptoms

Owners of affected 2025 Audi A5 and S5 models may notice that their "Air conditioning system does not work" and the "AC button automatically deactivates itself immediately." This prevents the air conditioning from engaging and cooling the cabin, leading to a lack of climate control functionality.

Fault Codes / DTCs

When diagnosing this Audi A5 AC malfunction, workshops have identified a specific diagnostic trouble code (DTC) logged in the vehicle's event memory. This fault code points to a software-related problem within the thermal management system.

| Code | Description | Module | | :--- | :---------- | | B16A1F0 | Refrigerant Shut-Off Valve, icing - water load too high | 00C5 (thermal management) |

Diagnosis / Trigger Conditions

This Audi A5 AC malfunction can be consistently reproduced during workshop testing. The customer complaint is that the air conditioning system is not working, and the AC button automatically deactivates itself shortly after it has been pressed. The root cause has been identified as a software issue residing in diagnostic address 00C5, which is responsible for thermal management functions. This software anomaly leads to the incorrect logging of the B16A1F0 fault code and the subsequent deactivation of the AC system.

Temporary Workaround

For existing vehicles experiencing this issue, a temporary workaround is available. The complaint can often be remedied by temporarily switching the ignition off and then on again. Additionally, the frequency with which this Audi A5 AC malfunction occurs is somewhat lower when the air conditioning system is operated on high or medium levels.

Important Warnings for Owners and Technicians

Audi has provided crucial instructions regarding this issue to prevent unnecessary repairs and costs:

• Do not replace components: Technicians are advised not to replace any components for this condition, as it is a software issue and replacing parts will not resolve the customer's concern.
• Warranty Inapplicability: This Technical Service Bulletin (TSB 2079225/1) is informational only and is explicitly stated as