I live in California and was getting my 1998 Expeditoin smogged, but did not pass due to a code reading of P0455. The guy at the smog facility wanted $125 for a diagnosis, but I thought that was way to much. Is there anyone that can kind of tell me what this code might mean and if it is something I can probably fix myself. I appreciate any help. Thanks.

 

p0455 is a problem with the evap emissions system. Alot of times caused by a loose gas cap,, but can be caused by alot of other things..

Click on the search button and search on p0455 and specify the engine forum.. You will have a bunch of past threads to look thru.