German Car Warranty and "Lemon Law" (Munich)

I bought a new new car and 4 days later the engine failed.
The car has now been waiting for repair for a month as the manufacturer says they don't have the proper parts.
They have not supplied me with a replacement or rental car.

Does anyone know what rights I have under German/EU consumer protection or lemon laws?

Any links or redirection to helpful contacts would be greatly appreciated!