When circuit boards were relatively new in cars, in the late 1970's, we had an Engine Management Control Board in our car.
It failed, the dashboard lit up like a Christmas Tree, and the car wouldn't run or even start. The AA Mechanic pulled the module out and the car ran perfectly. He suggested we buy another module, but they were very expensive. So we left it off. The car ran fine for another eight years. You can't leave them off in today's cars.
