I have a question - will a 2122 & 2127 code keep an engine from starting? My 03 3500 will not start after a multitude of problems that have been addressed. I now only have a 0541, 2122 & 2127 codes, but logically I think that this truck should still start. Also, where can I find an APPS for a late model 03 (the one that lives under the driver side batter)? Many thanks!