The check engine light went on and stayed on after I switched from regular to premium gas. I was using regular gas for years. What component seems to be affected? and how do I reset the light--or can I just forget about it?
check engine on 2000 Volvo S40
This seems like a coincidence, but either way I would check the diagnostic trouble code that turned on the check engine light and go from there. Some parts stores may read it out for free, try to get the code and post it and I can give you a more informed answer.
Tighten the gas cap. go to an auto parts store and ask them to read your code. If it is an evap code, ask them to erase the code. It is a very common Volvo code. Tell your gas jockey, which maybe you. Tighten the cap until it clicks a minimum of three times and never force extra gas in to round out the dollar amount. If the pump shuts off at 12.88, then that's what you pay don't try to force it to 13 bucks. 99% of the time you won't see the code again. owned many Volvo's and they all do it.