You can reset the service engine light on your Volvo 940 right at home. The On-Board Diagnostics computer keeps track of when your car needs to be serviced and lets you know by illuminating the service engine light. Oftentimes when you have the car serviced the light will automatically turn off or the mechanic will reset it for you. But many times this is not the case and the light remains on. But there is a very easy way to turn it off that requires no tools.
Put the key in the ignition and turn it to position "I."
Depress the trip odometer button on the instrument panel and hold it. Turn the ignition key to position "II."
Wait about five seconds until you notice the service engine light flashing. After about the fourth flash, while still holding the trip button in, turn the ignition key to position "I."
Release the trip odometer button and start the engine. The service engine light should now be off. If it's not, repeat the procedure.
