You can "reset" the CEL by disconnecting the battery for about 15 minutes and then reconnecting. The CEL will likely not re-illuminate for about 25 to 50 miles. BUT, if your state inspection uses an OBD II reader, it will indicate that even though the CEL is not on, there is an error. Here's the (first) next step: Have a friendly garage technician check your state's emissions regulations to see if certain car makes and models are exempt from the OBD II reading. This worked for me in Vermont when I had a problem with a vacuum leak, (later fixed with great tips from Brickboard readers!!!)

You can always open up the dash and remove the gauge cluster to pull the bulbs out. There are instructions in Chiltons, Volvospeed might have it too. Just pull the CEL bulb and Service bulb and you're all set.

A lot of inspection stations don't bother to actually plug in a OBD tool, they just look to see if the light is on.

There are a lot of codes that have no effect on emissions or drive-ability sometimes they go away as well. It's a good idea after you pull the bulbs to check the OBD every so often. Scan tools are pretty cheap now, under a 100 bucks in a lot of places.

If you have a 93-95 850, read the 700/900 FAQa section from the pull down menue at the top right of this screen.

For 1996-7 models, you can go to Autozone or Pepboys and have them read and zeroed out. If the problem still exists, you will have to get it fixed.

State inspectors also use OBDII code readers, so even if the CEL is not lit you will fail if there is a code present.

Klaus
--
1995 854T and 1998 V70R

You didn't state what is the model year of your 850 (they started when?), but if it's '96 or later, it probably has OBD-II diagnostics on board. That means that you have to use a special code-reading scanner to reset the light, rather than just a combination of pushing this button or that. A lot of consumer-grade scanners can read most of the codes, but only more expensive, professional scanners can reset it, so you'll probably have to go to a shop somewhere that can work on emissions equipment.

OBD-II has a more rigorous protocol, as you probably know, because it's supposed to ensure that the car follows more stringent emissions requirements -- they don't want to make it easy for you to circumvent the "check engine" warning.

Sorry.