Possible problem with dealership?

I have a 2007 Suzuki Reno that has 33,000 miles on the car. Recently it has been stalling and setting codes P0601, P2105, P2106. According to a local mechanic, this can only be solved by replacing the ECM due to the P0601. Due to the emission warranty still being in effect, I was told to take it to a dealer to have the warranty work completed. I have called the main corporate line and informed them of the situation. My problem is the fact that the closest dealer is 114 miles away. I contacted them and have an appointment set for tomorrow but I have a feeling I am being set up. They told me the diagnostics would have to be run first (as if having a local mechanics word wasent enough). But I am afraid that I will be told that the ECM will need to be ordered and I will be stranded. I asked them to reschedule so that an ECM could be on hand but they refused until the diagnostic was taken care of first. This sets up a red flag that I am about to be ambushed. Any suggestions?