I have a swap vehicle with a 2012 E38 computer, service number and OS are compatible. I have power hooked directly to the computer and starter. Computer is powered all the time. I have a 4 pole starter switch with only the battery and starter poles attached. I can turn ON the switch, start scanning, and as soon as I switch to start, the scanner shuts off. Motor spins just fine. This is a new build and cannot attempt to start at this time. I was checking everything to see if I had oil pressure and all other functions. Spark plugs are out and fuel pump is turned off. I was concerned that I was not getting RPM signal, but I guess if the scanner shuts off at start, I won't be getting RPM's. I have the dreaded 158mph reading---changed the speedo to Serial, but above problem has me stumped.