2011 Ford Fusion High Pressure AC

My AC is going out intermittently. I had it to the dealer and they could not replicate the problem. I have run Forscan while the AC is not working and the high side pressure is very high - 400-500 psi. It will get to about 430 psi then cutout. The pressure drops to 200-300 psi, the compressor comes on again, the pressure pegs out again and the compressor turns off. This usually happens when it is very hot outside and the car has been sitting in the sun. I did ask the dealer if he thought it was the pressure sensor, but he said he has never seen one go bad on this car. After driving for a while the pressures usually drop down and it will eventually work fine. However, that can be minutes to hours.

Anyone have ideas on how to diagnose or fix this? High end pressure when working is about 300 psi. Low end pressure about 30 - 40 psi. I’m worried about my compressor going out due to the high loads and the rapid cycling off and on. Thanks.

I’d take it to an air conditioning shop.

Yep, you’re out of warranty, search for a shop specializing in a/c. I used Yelp to help me find one for my MKX’s problem.

That indicates the expansion valve is malfunctioning.

https://www.rockauto.com/en/catalog/ford,2011,fusion,3.0l+v6,3015243,heat+&+air+conditioning,a/c+expansion+valve,6788

Tester