What Does P06A1 Mean?
The PCM has detected that the variable A/C compressor control circuit is reading lower than expected voltage. This means the control solenoid circuit is shorted to ground or the solenoid is drawing excessive current. The A/C compressor may be stuck at maximum displacement (maximum cooling/maximum drag on the engine) or may not respond to PCM commands. The driver may notice the A/C blowing very cold constantly or increased engine load.
Common Causes
30%
Short to ground in the wiring harness between PCM and A/C compressor control solenoid
30%
Failed A/C compressor control solenoid with internal short
20%
Damaged wiring insulation near the compressor due to heat or vibration
10%
Corroded connector at the compressor allowing moisture-induced leakage to ground
10%
PCM internal driver pulling the circuit low incorrectly
Diagnostic Steps
1
Disconnect the A/C compressor control solenoid connector and measure the solenoid resistance; compare to specification (typically 3-20 ohms). A reading near 0 ohms confirms an internal short.
2
With the solenoid disconnected, measure resistance from the PCM control wire to chassis ground; should be greater than 10k ohms. A low reading indicates a wiring short.
3
Inspect the wiring harness from the PCM to the compressor, paying attention to areas near the exhaust manifold, drive belts, and compressor clutch where heat and abrasion are common.
4
If the solenoid and wiring test good, monitor the PCM output duty cycle; it should modulate between 0-100% based on cooling demand. A stuck-low output points to a PCM fault.
5
Verify the A/C system charge level is correct, as some compressor control circuits behave abnormally with incorrect refrigerant levels.
Estimated Repair Cost
$100 - $700
Parts + labor, varies by vehicle and location
The PCM has detected that the variable A/C compressor control circuit is reading lower than expected voltage. This means the control solenoid circuit is shorted to ground or the solenoid is drawing excessive current. The A/C compressor may be stuck at maximum displacement (maximum cooling/maximum dr...
The most common cause of P06A1 (Variable A/C Compressor Control Circuit Low) is: Short to ground in the wiring harness between PCM and A/C compressor control solenoid
Typical repair costs for P06A1 range from $100 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle is safe to drive. If the compressor is stuck at maximum displacement, engine idle speed may be lower and fuel economy will decrease. The increased parasitic load on the engine is not harmful but is inefficient. In rare cases, a fully shorted solenoid could blow a fuse, disabling A/C entirely.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P06A1 to identify the root cause.
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Quick Info
Category
Powertrain
System
A/C Compressor Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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