Powertrain, generic · Computer and auxiliary outputs

P06A1 Variable A/C Compressor Control Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Variable-displacement A/C compressors change their swash-plate stroke via an electric control valve: a PWM current sets the crankcase pressure and thus the output. Where the engine module drives this valve (Ford's 'EVDC' compressors 2013–2019), it monitors the circuit; where the climate control module drives it (Hyundai, VW/Audi, GM), faults appear in that module instead. CARB requires monitoring only where the A/C affects engine control. P06A1 means the control valve circuit is too low – a short to ground, or the driver sees ground potential with the output off; shorted coil turns are another cause. No manufacturer document available to us names P06A1 itself; the description follows P06A0 and the Ford EVDC system. The compressor then delivers no controlled output.

Likely causes

Valve control wire shorted to ground (chafing at compressor or engine)
Shorted turns in the control valve
Moisture or corrosion in the compressor connector
Engine module driver faulty

Symptoms

  • A/C cools weakly or not at all
  • Code stored

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€30–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac compressor control valvevalve wiringengine control module

Related codes

P06A0P06A2P0646P0645

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.