QuestionI have a 91 Olds Trofeo, and I realize that it isn't a Caddy, but they are somewhat twins and the A/C system is the same. That is what I have questions about and I hope you can help me.
Everything was fine until about 1 month ago when I started getting B446 and B447 (A/C Refridge Low and A/C Refridge Very Low - Compressor Disabled) same as a Caddy.
I brought it to my mechanic who evacted the R12, pressure tested for 2 hours with Nitrogen (I think he used that), found no leaks and recharged with R134, cleared the codes and $310 later it should have been fine.
But it isn't...I am still getting the same codes.
I used my Service Manual and cleared the codes and checked BCM Input BI08 (A/C Pressure Switch Status) to see if it went "LO". It stayed at high which means the switch is OK and the manual tells me to leak test the system. It also says if both B446 and B447 are set, check low side sensor circuitry, if OK, evacuate and recharge system.
This has already been done!
I was thinking that it might be the Expansion Valve and was thinking of getting a Smart VOV - (Automatic Variable Orifice).
Also I noticed that there are different Low Pressure switches for R12 and R134, would that really make much of a difference?
I also read that the 85 - 93 Caddy (91 Olds Trofeo is Similar I believe) is not a good candidate for retrofit, and if you do, you should use 70 - 90% of the weight specified for R12 when filling with R134.
Any thoughts about this??? Any help would be greatly appreciated, as I hate clearing my codes every 3 min. Oh ya...When the computer is reset it blows nice and cold, but it appears the Low Side Sensor chills down way to fast according to BCM Data (BD28).
AnswerYou FOUND your problem. As you stated:
Also I noticed that there are different Low Pressure switches for R12 and R134, would that really make much of a difference?
The R-12 sensor is NOT calibrated for the R-134 freon and there is NO replacement switch yet available.
Your stuck to using R-12 freon.
