What is code 715 in the scanner when the mecanic check my car? on 2000 Mercedes-Benz C280

I have a little problem with the transmition and i scanner my car and came out code 715. Some people toldme that i need to buy the plack of the valvule sistem and the plug and put it and everything will be allright. Can you tell me that is thrue. thank you.

Asked by for the 2000 Mercedes-Benz C280