2021-2023 Audi AC Not Cooling TSB 2063575/2

Audi has issued Technical Service Bulletin (TSB) 87 22 28 2063575/2, dated July 12, 2022, to address concerns regarding the air conditioning system in various 2021-2023 Audi models. This TSB, which supersedes Group 87 number 21-15 dated June 16, 2021, provides comprehensive guidance for diagnosing and repairing issues where the Audi AC not cooling properly or at all.

Symptoms

Owners of affected Audi vehicles may experience their air conditioning system not blowing cold enough, taking an extended period to cool the cabin, or failing to cool at all. Diagnostic checks often reveal insufficient refrigerant circuit head pressures and a low or empty refrigerant volume in the system.

Fault Codes / DTCs

When the refrigerant volume is very low or empty, the Heating/Air Conditioning Electronics control module (E87, address word 0008) may store the following diagnostic trouble code:

Code	Description	Module
B10AE21	High-pressure sensor Lower limit not reached	Heating/Air Conditioning Electronics (E87)

Diagnosis / Trigger Conditions

Diagnosing the root cause of an Audi AC not cooling issue involves a thorough inspection of the refrigerant circuit. Initially, refrigerant circuit head pressures are checked, and the refrigerant volume is recovered. If the volume is found to be low or empty, leak identification dye is added along with a full refrigerant charge, and the vehicle is test-driven.

It's important to note that a halogen leak detector is not the most reliable method for precisely locating refrigerant leaks, especially within the evaporator core where direct access is limited. A false positive evaporator core leak reading can occur if free refrigerant migrates through the fresh air intake into the evaporator housing from a leak elsewhere in the cowl or engine compartment. Audi strongly recommends using calibration gas as the diagnostic method, following the procedures outlined in TSB 2064077 87 Air conditioning refrigerant circuit diagnostic method using calibration gas.

Important Warnings for Owners

This TSB provides crucial information for both technicians and owners regarding the proper repair of AC system leaks:

• Warranty Coverage: This Technical Service Bulletin is for informational purposes only and is not applicable to any Audi Warranty. Owners should discuss potential costs with their service center.
• Evaporator Core Replacement: Do not replace only the evaporator housing with the core assembly. Do not loosen or remove the expansion valve from the evaporator core connections, nor disassemble the evaporator housing assembly. If the complete evaporator housing assembly is returned for analysis incomplete, disassembled, or with non-original components, the warranty claim will be debited.

Repair Procedure Summary

1. Initial Assessment: After confirming insufficient refrigerant volume and potential DTC B10AE21, add leak identification dye and a full refrigerant charge, then test drive the vehicle.
2. Systematic Leak Check: Conduct a thorough visual inspection of the refrigerant circuit under UV lighting. Systematically check all components and connections for leaks. Pay close attention to the connection junction at the evaporator core, expansion valve, and refrigerant lines.
3. Expansion Valve Repair (Primary Solution): If a refrigerant leak is detected specifically at the evaporator core/expansion valve/refrigerant line junction, the recommended repair is to replace the expansion valve and all four O-rings. The evaporator core itself should not be replaced at this stage. Technicians are required to document the leak with a video and photograph any damage to the expansion valve ports, damaged O-rings, or refrigerant line connections.
4. Evaporator Core Replacement (Last Resort): Only if all other leak possibilities from the expansion valve connections and other refrigerant circuit components have been systematically excluded, and the evaporator core is definitively identified as the sole source of the leak, should the evaporator housing with evaporator core assembly be replaced. This replacement must include a new expansion valve, retaining plate, bolts (from small parts kit 4M0 898 037 A), and all four O-ring seals.

Required Tools or Parts

For proper diagnosis and repair of the Audi AC not cooling condition, technicians may require the following:

• Small parts kit: 4M0 898 037 A (for evaporator housing replacement)
• Electronic Refrigerant Leak Detector: Various types
• Automotive A/C Nitrogen Leak Test Kit: NITROKITG
• VAS tester with ODIS: VAS 6160/VAS 6150 (running the current version of ODIS on Windows 10)

Owner Action

If you are experiencing issues with your Audi AC not cooling, it is recommended to schedule an appointment with an authorized Audi service center. Inform them of the symptoms you are experiencing and mention Technical Service Bulletin 87 22 28 2063575/2. The diagnostic process can be complex, and specialized tools and procedures are required to accurately identify and repair the refrigerant leak.

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Source: NHTSA ID: 10216020