Air conditioner fluctuates cold and warm

The compressor clutch engages and the air conditioner is blowing forty degrees F out of the vent with a thermometer and then it will not hold that temperature after backing out of driveway from an idle speed. It also has a check engine light on the one below the gas gauge. I put my scanner on it and I got no codes. So my problem is an intermittent conditioner blowing cold then warm with a check engine light.

I can see the clutch on the compressor staying constantly engaged. With the compressor running and the high and low side gauges hooked up I have 37 psi low side and 210 psi high side. Today I had about 48 degrees F coming out of vent with thermometer. My static pressure on the gauges with the engine shutdown is: both sides reading 114 psi at 86 degrees outside air temperature. I also have a check engine light on and my OBD2 scanner cannot detect a code number. I verified the gas cap was seated properly and it is an original gas cap. I was reading that some home scanners will not be able to read certain codes and only can be done with a more advanced code reader. I also disconnected the battery and the code cleared but returned after fifteen miles of driving and still the scanner will not retrieve a number of that code while the CEL is on. As far as the air conditioner where should I troubleshoot next? Parts store says that the full charge is.9 lbs of R134. Based on my gauge numbers what should I do. Yesterday compressor ran and suction line did not even get cold and unable to feel cold air from vent. Possible blend air door actuator? Owner said someone replaced compressor last year and not sure if mechanic evacuated it properly because mechanic was kind of wishy washy.