Most air conditioning compressors in modern cars utilize variable displacement technology, which means the compressor is always driven by the engine and controlled by the engine control unit ( ECU ) through the compressor control valve ( CCV ), allowing for linear control of the compressor from 0% to 100%.
This enables the compressor to adapt to current driving conditions and heat load, while being fuel efficient at the time: maximum output on hot days or at engine idle, reduced output while cruising on the freeway or cooler days.
Like every part in a car, the control valve can fail, which is not uncommon.
Failure might be experienced by some of those symptoms:
- A/C is sometimes very cold and sometimes cooling very little or not at all
- A/C might take some 10 to 20 min to start cooling, but then works fine
- A/C performance is sluggish, and does not cool the car on hot days
- no change after a regas service, especially if one of the above symptoms is present
The good news is that in most cases only the compressor control valve needs replacing, not the whole compressor.
So how does the control valve fail?
1. Electrical Failure- damage ( often rust ) to wiring harness or plug and contacts ( safe to replace )
2. Mechanical Failure Compressor - metal filings from the compressor can block the valve; here it does not make sense to replace the valve as the compressor will fail soon ( not safe to replace )
3. Mechanical Failure Valve - most common - the plunger simply stops moving all the way: it is constantly moving back and forth, pushed forward by a small magnetic field and supporting spring. If the spring gets tired or fails, the plunger can no longer overcome the high refrigerant pressure and control the compressor to pump 100%. ( safe to replace )
If you would like to book this repair for your car in Perth, WA, please complete an Online Booking and choose the option 'Inspection' - and leave a note with more details about the required repair.
All repairs include a 12 month warranty
This is a common failure in Valeo, Sanden, Zexel and Denso compressors used in cars made by VW, Audi, Mercedes, Hyundai, Volvo, Toyota and many more