The check engine light in your Dodge Avenger comes on when you need to perform regular maintenance on your vehicle, and will stay on until you reset it. The on-board diagnostic computer is what causes the light to come on, initially. This computer generates and stores various trouble or fault codes that indicate that service is required. Once you have fixed your Avenger's problems or performed the required maintenance, you need to know how to reset the check engine light.
Open the fuse panel in the driver's side footwell by pulling down on it with your fingers.
Locate the fuse for the electronic control unit. Use the fuse diagram on the underside of the fuse cover. The fuse will be marked "ECU."
Pull the fuse for the ECU, using the fuse pullers in the fuse panel.
Turn on the ignition but don't crank the engine.
Wait 5 minutes and then replace the ECU fuse. The "check engine" light will blink and then shut off. This will reset the light.