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The Oil Level Sensor is in the front passenger side of the oil pan. Check the wiring, connector, and harness. They have been known to fail. if you are a conscientious owner and perform weekly underhood checks you can simply disconnect the sensor connector (the message should disappear) and maintain the oil level at the proper height - < ==== ADD XXXXXXXXXX == on the dipstick.
Your proper oil fill, with filter, is 7.5 quarts, and that will place the level at the X's shown above.
The oil level sensor is a reed switch in a wand, with a magnetic float/trigger. Oil level drops and the magnetic float closes the reed switch, setting the message. The sensor is about $25 in Rock Auto and can be replaced with some dedicated labor with the car up in the air and the lower air deflector removed.