Does a ignition switch on E300 have to be key coded?

Yes, the ignition switch on a Mercedes-Benz E300 typically needs to be key-coded to the vehicle's electronic system. This process ensures that the vehicle recognizes the key and allows the engine to start. If the ignition switch is replaced, it may require reprogramming to sync with the existing key and immobilizer system. Always consult a professional or the vehicle's service manual for specific procedures.