Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
How long have you waited for? Sometimes it can take several hours of driving time before it resets and says "code"
I have seen up to 24 hours of ignition on and radio on time necessary to get the radio off of wait. If it doesn't come off of wait, the radio will have to be replaced. Obviously you can't leave your ignition and radio on for 24 hours without killing the battery so a large battery charger is necessary in order to do this procedure. You need a battery charger capable of at least 30 amps.
I have seen it take only a couple of hours of constant ignition on time for it to finally say "code". There is no telling how long it will take. Did you type the wrong password ***** and that is the reason why it says "wait" or did it just happen on its own?
Not engine running but key on, engine off. You could leave the engine running and that does the same thing essentially except wastes gas. This is the only way, I've dealt with hundreds of these radios. The "CODE" message appears whenever the battery was disconnected or jumpstarted. If the incorrect code was entered 3 times, it then turns to "WAIT" and there is nothing you can do but wait.
I would keep driving the car and eventually it should say "code". If not the dealership will have a battery charger big enough so that when the key is turned on, it won't drain the battery.