B0642moderate severityBody
A/C Compressor Circuit
on 2012 Audi A6 3.0L Supercharged V6 · AWD
What this code means
Malfunction in the A/C compressor electrical control circuit.
Symptoms
- A/C not cooling
- Compressor clutch not engaging
- Compressor clutch always engaged
- A/C system cycling abnormally
Common causes
- Faulty compressor clutch coil
- Compressor control valve failure (variable displacement)
- Wiring damage
- Ground circuit issue
- Clutch air gap incorrect
Diagnostic steps
- Test compressor clutch coil resistance
- Check clutch air gap
- Test control valve (if variable)
- Inspect wiring and ground
- Measure voltage at clutch connector
Repair notes
Replace compressor clutch coil or adjust air gap. For variable compressors, replace control valve.
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