2021-2024 Audi A/C Not Cooling TSB 2063575/3

Audi has issued Technical Service Bulletin (TSB) 2063575/3 to address customer complaints regarding the air conditioning system not cooling effectively in various 2021-2024 models. This issue can manifest as the air conditioning not blowing cold enough, taking an extended period to cool, or failing to cool at all. The TSB provides updated diagnostic and repair procedures for technicians to accurately identify and resolve refrigerant leaks.

Symptoms

Owners may experience their Audi A/C not cooling, with the following observations:

• The air conditioning does not blow cold enough.
• The system takes a long period of time to cool the cabin.
• The air conditioning does not cool at all.

These symptoms often indicate a low or empty refrigerant volume within the A/C circuit.

Fault Codes / DTCs

When diagnosing the issue of the Audi A/C not cooling, technicians may find the following diagnostic trouble code (DTC):

• B10AE21: High-pressure sensor Lower limit not reached (stored in the Heating/Air Conditioning Electronics control module, E87, address word 0008).

Diagnosis / Trigger Conditions

Initial diagnosis typically involves checking the refrigerant circuit head pressures. If these are insufficient, and the refrigerant volume is found to be very low or empty after recovery, a leak is suspected. Historically, technicians might add leak identification dye and test drive the vehicle. If an electronic refrigerant leak detector alerts at the central vents or condensate drain, the evaporator core might be incorrectly suspected as the source of the leak.

Audi notes that a halogen leak detector is not the most reliable method for pinpointing refrigerant leaks, especially in evaporator cores where direct access is limited. The TSB strongly recommends using the calibration gas method outlined in TSB 2064077 87 Air conditioning refrigerant circuit diagnostic method using calibration gas for suspected evaporator leaks. This ensures a more precise diagnosis when the Audi A/C not cooling issue is present.

Important Warnings

Audi has provided critical warnings for technicians regarding the repair process:

• Do not replace only the evaporator housing with core assembly.
• Do not loosen or remove the expansion valve from the evaporator core connections in any way.
• Do not disassemble the evaporator housing assembly in any way.
• For Q5 models, if evaporator replacement is performed, it is crucial to loosen and refasten the Relay and Fuse Carrier 3 -SR3- in its correct original position during reassembly. Failure to reinstall the Relay and Fuse Carrier 3 precisely will result in water intrusion and subsequent component damage.
• Any complete evaporator housing assembly, expansion valve, bolts, and o-ring seals submitted for warranty that are incomplete, disassembled, or confirmed not to be original components will be returned to the dealer, and the claim will be debited.

Repair Procedure Summary

The TSB outlines a systematic approach to resolving the Audi A/C not cooling problem:

1. Initial Leak Check: Thoroughly check for refrigerant leaks at every component and connection in the refrigerant circuit. Systematically exclude potential causes.
2. Expansion Valve Focus: If the evaporator core is still suspected as the sole leak source after other areas are ruled out, carefully inspect the connection junction at the evaporator core, expansion valve, and refrigerant lines for any overlooked leaks (as shown in figures 2 and 3 of the TSB).
3. Expansion Valve Replacement: If a leak is confirmed at the evaporator core/expansion valve/refrigerant line junction (evidenced by residue from contrast agent, as in figure 4), technicians should record a short video. Then, replace only the expansion valve and all four O-rings. Re-test the system to confirm the leak is resolved without replacing the entire evaporator core.
4. Evaporator Core Replacement (Last Resort): If all leak possibilities from the expansion valve connections and other refrigerant circuit components have been excluded, and the evaporator core is definitively the only remaining source of the leak, then the evaporator housing with evaporator core assembly, along with the expansion valve, retaining plate, and bolts (included in small parts kit 4M0 898 037 A) and four o-ring seals, should be replaced. The assembly must be carefully packaged as a single unit for submission and laboratory analysis.
5. Relay and Fuse Carrier Reinstallation (Q5 Specific): For Q5 models, if the evaporator is replaced, the Relay and Fuse Carrier 3 -SR3- must be loosened and then precisely refastened in its original position during vehicle reassembly to prevent water intrusion and component damage.

Required Tools or Parts

To perform the diagnostic and repair procedures for the Audi A/C not cooling issue, the following tools and parts may be necessary:

• Small parts kit: 4M0 898 037 A (includes evaporator housing, expansion valve, retaining plate, bolts, and o-ring seals)
• Electronic Refrigerant Leak Detector
• Automotive A/C Nitrogen Leak Test Kit: NITROKITG
• VAS tester with current ODIS (Windows 10): VAS 6160 / VAS 6150

Owner Action

If you are experiencing symptoms of your Audi A/C not cooling, such as insufficient cooling or no cooling at all, and especially if you have received a diagnostic code like B10AE21, it is recommended to schedule an appointment with an authorized Audi service center. While this TSB provides detailed repair instructions for technicians, it is informational and not applicable to any Audi warranty. Your dealer can perform the necessary diagnostics and repairs using the procedures outlined in TSB 2063575/3.

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Source: NHTSA ID: 10241434