I have a 1999 A6 Quatro. That sat for about 10 months while I was sick. replaced fuel filter, Plugs, wires, battery. The cars starts fine and drives fine except it will not go faster than 20 MPH. I have read several threads that make me believe it is in Limp Mode. What is the exact procedure to get it out of limp mode?

Thanks in advance.

 

Pull the OBD codes from the ECU first.. Document them. Before you do the next few steps, make sure you have the unlock code for the radio in your car. Now disconnect the positive terminal from the battery. Touch it to negative terminal or the car body to effectively discharge any power storage devices. Let the car sit for an hour or so with the battery disconnected. Reconnect the battery. When attempting to start the car, turn the ignition switch to the ON position but DO NOT engage the starter. Let the ignition switch set in the ON position for about 15 seconds. Then start the car. It may stumble a bit at first but it will catch and run after a few seconds. This totally resets the ECU and dumps any "bad memories" it may have had. Take it for a drive and see if that fixes it.