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A/C cooling is weak and gradually loses performance

Q: How to fix A/C cooling is weak and gradually loses performance in Audi S5 Cabriolet?

Customers reported lack of cooling from the air conditioning system. The diagnosis confirmed an insufficient amount of refrigerant. A leak was identified in the condenser (air conditioning radiator), specifically in the place where the cross pipes connect to the collector tank, which resulted from weakening of the soldered connections. The solution to the problem was to completely replace the faulty condenser.

in Audi S5 Cabriolet (2017-2018)

Symptoms

No cold air from vents

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Technical diagnosis (Premium)

Recognized technical fault:

Auxiliary controller voltage instability detected

Technical analysis

Detailed analysis of HVAC controller operation parameters, CAN bus data readings, and diagnostic signal waveforms. Purchase PRO access or log in to read the full fault analysis.

Confirmed solution

Complete step-by-step repair procedure including module non-volatile memory reset, sensor calibration, and correct wiring routing. Unlock the full report to see the instruction.

Parts needed

Filters ferrite anti-interference / noise suppressor
Auxiliary starting battery (depending on cell status)

Workshop hacks

Important workshop tips for mechanics regarding bypasses without expensive control module replacement and manufacturer software service bulletins.

TSB / TPI service bulletins

TSB-24-HVAC-01TPI-2068943/2

A/C Technical Specifications

2,3

Refrigerant: R134a Amount (g): 750 – 800g Oil: G 052 154 A2 PAO 68 lub PAG ISO 46 Oil (ml): 250 – 300ml

Standard

Refrigerant: R134a Amount (g): 650 –700g Oil: G 052 154 A2 PAO 68 lub PAG ISO 46 Oil (ml): 250 – 300ml

kompresor Zexel/Denso

Refrigerant: R134a Amount (g): 600g Oil: PAG PAG 46 lub PAO 68 Oil (ml): 150ml

See full specification

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