My wife is driving home from work in our S4 and is just about to get onto the highway on-ramp when the car dies. She tries and tries but the car would not start. It was acting as if it was out of gas but it had more then half a tank. As I'm on the phone I tell her to try and switch to the stock APR program to see if that help. If you have the APR software you know you can switch it with the cruise control and can pick the problem by the number of times the CEL flashes. Well after holding the cruise control button for 60 seconds the CEL was not flashing. First thing that comes to mind is that the ECU is dead. Long story short I get a ride out there and my friend Erik that owns I.P.M. Auto Service meet met out with no luck getting the car started. His Vag-com kept getting a message of "unable to communicate with ECU". At that point it was becoming clear that either a relay(s) that powers the ECU was not working or the ECU was completely dead itself.
I get the S4 towed to his shop and we check all of the fuses and relays to find all were good. Next day after talking with Achtuning I get to borrow a ECU to see if the car would start. Sure enough plug it in and the car fire right up. So I buy this ECU from them and the car is good to go.
With the ECU I got from Achtuning it came with MTM software vs. APR software. I'm actually liking the MTM software better since I'm boosting around 18-20psi vs. the APR software boosting around 15-16 psi.