P0647low severityPowertrain
A/C Clutch Relay Control Circuit High
on 2017 Audi S5 3.0L Supercharged V6 · AWD
What this code means
The PCM detected a high voltage condition in the A/C compressor clutch relay control circuit. This may keep the A/C compressor from engaging correctly.
Symptoms
- No A/C cooling
- Compressor clutch not activating
- Check engine light on
Common causes
- Open in control circuit
- Short to voltage in wiring
- Faulty A/C clutch relay
- PCM driver failure
Diagnostic steps
- Read stored codes
- Check circuit for open or short to power
- Test relay coil resistance
- Verify PCM output signal
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