F47, thats the low refrigerant code. I should have known that one.
Problem is it can be a few things other than being low on freon.
The sensor that detects this is just past the orifce tube.
It is quite common for a compressor to fail and contaminate the entire system with metal shavings.
After all new parts are put on it works good for awhile until the shavings migrate through the lines and collect on the o-tube.
It gets plugged up and creates a low pressure condition on the other side. The sensor sees this as low freon.
Also you could have a bad sensor or a computer problem. By the description of your symptoms I would pull down the system and check the o-tube for blockage.
Also an overcharge of oil will do the same thing. If oil just pours out the line when the o-tube is pulled a system flush is probably in order.
If neither of these concerns are present then recharge the system and procede with the sensor/ circuit diag.

 

E52 just means the battery has been disconnected. I don't remember E91 ,I have the chart at work.
E91 PNDL switch problem.

 

are you using R134 or R12?
If R134 this may be your problem under certin contions the 134R trigers the computer to say the A/C presure is out of range R12 seem to be the fix at this time however a full flush may be need.

 

I you upgrade you A/C to R134 I have bad news for you.
You may need to start over flush every thing and go back to R12 it appears to be a problem in some cadies with digital dash the pressure switch gets fake out by the R134 gas and set a code long story short.