When you try to recharge the A/C system on your Reatta you may find the compressor will not engage. The reason is that once the BCM detects a very low freon condition in the A/C system it gives and error message and disengages the compressor. To get the compressor to engage again the BCM codes must be cleared by resetting them through the computers diagnostics screen. The codes can also be reset by removing the negative battery cable for a couple of minutes and then reconnecting it.  If you don't get enough freon into the system quickly after resetting the codes the BCM will disengage the compressor again and you will need to repeat the procedure for resetting the codes.

Instructions can be found on this website for resetting the codes using the built in computer diagnostics system.