Many Toyota Highlander models are equipped with maintenance reminder systems that alert the driver when regular maintenance should be done. Oil changes are the most common reason for the maintenance reminder to illuminate. When the oil is changed by a Toyota dealer, the light should get reset as part of the process. You can reset the maintenance required light yourself if your mechanic does not reset it or if you perform the maintenance yourself.
Turn the ignition switch to the “On” position but do not crank the engine.