I have a 98 e430, and I went through and changed all the fluids when the car was purchased, as well as the air filter. I did the work myself. Now 6 months later, I have a wrench display on my dash every time I start up. I called the dealer, and they indicated they would reset the service indicator, only if they preform the oil change, or the service. Is there a way I can reset this or does this require any special tools?