07 Ram 1500 no crank or ecm communication after motor change

[Skribble93]

Hi everyone i encountered a odd to me issue whilst working on a friends 07 Ram. He bought the truck being told the motor had been changed but never finished. We finished getting the cab back in place and got everything hooked up but when we went to see if it would start and run we got nothing at all just dash lights. The motor is from an 04 ram 1500 5.7 hemi same as the 07 all sensors that were needed were swapped out as well as the valve covers and coils to plug in to the 07 harness. If jumped the starter works and turns the motor but no fuel or spark. A friend that has a rather expensive Snap on computer stopped and hooked up to it and it reads no communication with ecu or any computer in the truck for that matter. We tried another known good computer and same result all that works are dash lights and exterior lights checked the neutral safety switch and all common things that could cause an issue same as fuses and ground/power wires but no change. The computer is getting power to it but nothing from there on the scanner also kept coming up with the engine vin not matching the ecu. Is this a dealer flash fix or something we are missing? Any help would be greatly appreciated the owners business depends on having a truck and we are all at a loss.

 

[MikeT]

I'm not real up on this but I believe between 04 and 06 the Ram computer systems and/or their communication systems was changed. The 07 has whats called canbus and the 04 is an older but non compatible bus system. There are several folks on here that are much more knowledgeable than I am, I'm sure they will reply soon.

Mike

 

[Rlaf75]

I dont know about the year compatibility but make sure al ground connections are good. Check the harnesses for pinch/cut wires. Also check the fuses. Sounds like a mess was purchased so anything is possible not knowing the truck