BJF

I have a 300 ES that has the engine light come on every now and then as well. Mostly when it is around 0 degrees outside. I had it checked by a garage (not a dealer) and they said the engine light came on because the engine must have knocked. Anyway the light is on and off all the time, the car runs perfectly though. Any advise? Today the track off light also came on, so I have both at the moment.