Robert, I posted about this issue last week. Got zero responses. I think this is a very dark and infrequently travelled thread (unlike winter tires). I have been in your situation since my car had 1500 miles on the clock. The check engine light keeps coming on every couple of months. Last time I took it in, the Volvo rep got involved. He ordered a new gas tank, which didn't solve the problem (they put the original tank back on). I have had a new gas cap (first occurance), new charcoal canisters (1 or 2 now), check valves (2 or 3), rollover valves (1 so far) installed and the light kept coming back on. I really think that there is something wrong with the design of either some component or the diagnostic software. Almost every time I brought the car in with the CE light I was told "We couldn't find anything wirong, but replaced xxx part just in case and reset the trouble code". This tells me that there IS NO problem and the code gets set FALSLY.

Now on to the inexpensive code scanner. I went to AutoZone last week and purchased an OBDII scanner made by Actron for $150 (Actron advertises it on their website for $200). The scanner told me that there were no codes set, but when I followed the procedure for clearing codes, the CE light went off. So the question I posted here last week was: does anyone know the corellation of OBDII codes to Volvo codes? The OBDII standard specifies four sets of codes. I know that I usually get the 611 Volvo code (small fuel vapor leak or some such thing). Obviously, the Actron tool didn't pick it up, though it managed to clear it. My concludion is that the code that was set by my Volvo was not a standard OBDII code, but rather a proprietary Volvo code. Thanks, Volvo for making the car MORE capricious than required by law. If anyone knows anything about any of this, please, enlighten me because I am in the dark here.

Vladimir

P.S. Love the car. Drives like a dream and I don't want to get rid of it. It WILL fail anual inspection with the CE light on, though, so black tape solution is not an option. Also ignoring the CE light is not a good idea for it may cry wolf may times, but then there will really be a wolf...