wallet sensor
The sensor installed inside the drivers seat of most modern vehicles. It is designed to detect the thickness of the drivers wallet and activate when the drivers wallet becomes too fat. It usually triggers vague and inconsequential check engine lights that can only be diagnosed and fixed by the dealership at an exorbitant price. The sensor is usually designed to activate about 3-6 months after the car is out of warranty. Once the sensor has detected that the wallet has become sufficiently thinner it will then wait 6-9 months before reactivating and will continue to do so in perpetuity.
The wallet sensor triggered my check engine light. Only the dealership has the equipment to read the code. They said it will be $300 for a diagnosis.