Please help with a Sienna 01 code problem

[sandybee]

HI, I'm trying to find out some information about a 2001 Sienna that my Dad owns. He has been having AC problems, (wasn't getting cold air, clutch wasn't coming on) ran the test and came out with an error code of 23, which is supposedly the pressure switch.

He takes it in to a mechanic, not a Toyota place, and they tell him that he has a leak somewhere, but "they can't find it". The guy told him he had 4oz of freon in the van and they had to add an addt'l 18oz. They put the dye through the system but can't find the leak.

My question is, who is right? The code is saying it's the pressure switch but the mechanic says there is a leak. Is the mechanic way off? Should he take it in to a Toyota place instead?

My Dad is older and we don't want him getting ripped off by getting work done that may not need to be done. Any help would be greatly appreciated. Thanks in advance.

-Sandy