What are the symptoms of Unusual noise and metallic grinding when A/C is on in Audi S7 (2019-2022)?

Weak cabin cooling. Clicking or rattling behind dashboard. Dark sludge or metal shavings in system

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Unusual noise and metallic grinding when A/C is on

Q: How to fix Unusual noise and metallic grinding when A/C is on in Audi S7 (2019-2022)?

Replacing the expansion nozzle + replacing the condenser + flushing the entire system with a specialized machine + replacing the compressor (TSB 2061277/2). If only the dehumidifier is to blame: replace the cartridge + rinse. Rattling noise only with AC + no errors = almost always choke or dryer. Repair without replacing the compressor is possible if intervention is early.

in Audi S7 (2019-2022) (2012-2022)

Symptoms

Weak cabin cooling
Clicking or rattling behind dashboard
Dark sludge or metal shavings in system

DTC error codes

None or low pressure faults

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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

Refrigerant specifications for this model are available in the catalog.

Open refrigerant database

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