I am going to post this info in here instead of starting a new thread as I think it is kinda related....
my current problem was I could get my code reader to read sometimes... but my dakota digital dash BIM would not communicate at all. The engine runs fine and all engine systems (sensors) are working properly. After a few days of investigating I was able to determine that the newer engines run a CANBUS network and it requires a 120ohm resistor at each end. My issue was a 120ohm resistor at the ECM plug only (I needed another resistor at the end of the canbus). This past weekend I bit the bullet & with guidance from friends (far more electrical knowledge than I) I de-pinned the data wires from the OBD2 port (my end of the canbus) and after gently "de-skinning" a portion of both wires I soldered a automotive 120ohm resistor a few inches from the OBD2 port termination. I checked the ohm reading at the ends and was consistantly reading the required 60ohm +/- of which I was:62.3- 62.5 ohms. I plugged the BIM module in & reconnected the power, I turned the key on and the gauges all appear to be working..... WOW!! RELEIF! I started the truck & all the gauges were operating. I then coated everything in "liquid electrical tape" and then wrapped that in regular electrical tape. I started the truck again & the gauges are still operating correctly - I also connected the code reader & it also connected right away.... relief!...LOL!
so summarize: if you have a genIV engine with a (X38 ECM) then you will need to have 60ohm +/- at the OBD2 port. and will need 2 120ohm resistors each end of the canbus network. I believe(??) there is 1 resistor at the ECM plug- but not 100% sure.
I hope that others will find this a help if needed. although I am gathering that most do not use the OG harness and equipment.
