I need radio help please!

[mavrick0]

Another possibility is while in the menu you switched model memories. So now it's on a memory that is defaulted back to factory settings versus the memory that the model was setup on.

I also just looked at the rc4wd page under the 4200 and there's a couple of notes for the radio. One was that the pump and light switches must be turned off before turning on the radio. That might be causing your issue too.