Most model years of the Volvo S40 are equipped with a maintenance reminder light that is designed to inform the driver when it is time for regular maintenance, such as oil changes. When an auto mechanic performs the service on the S40, he will typically reset the maintenance light as part of the process. If the mechanic neglects to reset the light, or if the owner performs the maintenance himself, the owner can reset the maintenance light manually.
Press in the trip odometer reset knob. Hold the knob down.
Turn the ignition switch to the "II" position. Do not start the engine.
Hold the odometer knob down for about 30 seconds until the maintenance light blinks. Release the trip odometer knob.
Turn the ignition switch off.