Just wanted to pass this along. I picked up a cheap ($88) PC interface box that can hook to a laptop PC and let you run standard ODB 2 diagnostics (96 and up) on a volvo or most any other make of car or truck. Software to load on the computer is free and will run under any version of windows or you can get a dos based version if you want to try it on a really old laptop. It will need an available serial port (9 pin), but if all you have is USB then you can buy one of those usb to serial converters for a few bucks more. I ordered this unit and got it about 3 days later. Works pretty well for what it costs. Here is the website if you are so inclined: http://obddiagnostics.com/

I had a check engine light on for a while now and assumed it was the PNP switch, but it was a P0410 which is "Secondary Air Injection System Malfunction". Since the air injector pump is sorta hanging on broken mounts right now, I guess that may be part of the problem. Anyway, it let me clear the check engine light and showed other data including the O2 sensor operation, fuel pressure, engine temp, etc. All in all, a pretty cheap way to check your engine compared to a handheld code reader which usually goes for over a hundred or more and will only show the codes stored on the vehicle computer. As for the usual disclaimer, I have no connection with the guy selling this system, just a satisfied customer.

Now if you want a more delux variant on the above theme, you can look at http://www.obd-2.com/#products . They sell a similar type of scan tool that hooks to a pc as well but has a more robust software program that can read the standard ODB2 codes as well as the manufacturer specific ones. My brother owns this system and used it on my Ford truck over the holidays. Again, it works well but it is more expensive than the system I've got. After being nicked 90 bucks at the local ford dealer to read the codes on my pickup truck and then have them tell me they wanted an additional 200 or so to replace "one" of my coil on plugs ($50 part on the front of the engine), I decided it was time to get my own code reader. I could have saved the cost of the tool for the 90 dollar service charge. Live and learn.

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97 S90 with 162K miles still going strong