I have a 2001 Mercedes CLK. The other day the AC stopped blowing cold suddenly. I checked the Freon charge and the low side appeared to have way too much pressure. I checked for fault codes, found B1423- switchover valve block (Y11), and checked AC diagnostic data, which seemed fairly normal. I cleared the code and it has not returned. What typically would cause this condition? I have been told it could be a bad compressor or a blockage of some kind. Any help would be appreciated.