Hello all, first post. Read allot of helpful info on here in the past. My truck is an 2000 2500. It was an auto truck and I swapped a 5 speed into it about a month ago. Been doing great, this Friday I installed a FASS DRP and a big line kit to keep my VP44 happy. Got it all done, started the truck and checked fuel pressure at 15psi. Gave it a couple revs and it wouldn't rev over 2k, would defuel itself. That's when I seen the "NO BUS" message. Only gauge that works is the tach. Pulled codes through cluster and get 920, 921, and 999. Cluster check shows all gauges and lights are good. I have spent the day cleaning all connections, pcm, ecm, cluster, bulkhead connnectors, battery cable ends and such. Alternator is not charging, and I know the PCM signals the alternator. PCM has power to it. What's strange is if you drive it, it will give you full rpms and power. But if your just sitting still it will defuel at 2k. My brain is telling me this is simple since all I did was install a lift pump that uses factory brackets and connectors. But until I can get my hands on a wiring diagram I am stuck. Appreciate any and all help! 

Edited October 21, 20186 yr by Moneypit2000

Sorry for late post, I do hope it's something simple too but I'm not to strong on electrical, part of reason I didn't post sooner was waiting on more knowledgeable members. 

All I can say is you're right about charging, PCM is what controls it, now why did it quit is another question. 

Lately there been a lot of issues with alternators and ac noise associated with them taking out electronics. So once you figure out why it's not charging it's worth looking in ac noise and ground mods.

For now maybe charge batteries and unplug alternator all together to see if truk runs any different (charge wire and field plug). 

Plus you had auto now it's manual and ecm/pcm still the same I assume, you may have to reprogram them but I'm not sure. Probably if you went the other way manual to auto then you would for sure.

Hopefully someone will point you in right direction soon. Good luck.

Check the two bulk connectors that run along the cowl to the right of the valve cover.  Make sure the plastic bails are closed and tight.  I've seen where a loose connection there will cause CCD bus issues.  Plus, it's right at shoulder height for when you're working on the lift pump area.

Thank you for the replies! I've driven the truck close to a month after the swap, only altercation to the wiring was to ground the middle wire on the three prong plug for the truck to start. I have opened, cleaned and reseated those two bulkhead connectors twice lol. I appreciate all the help!

I worked at a Ram/Chrysler dealership for a year and became good friends with the older tech that had been there for years, he knows these trucks up and down . He was kind enough to give me complete wiring diagrams and pin outs for the PCM, ECM, Cluster and CCD bus comm. I have ran continuity tests from PCM C3 connector to cluster on Bus - and Bus + and the same for the ECM bus - and bus + circuits. I have good continuity through the entire harness. I have Power to Pin 22 Red/White on C1 at PCM. Also have good ground. What else do I need to check before I go and buy a PCM? I HATE diagnosing problems as the computer, because it just makes you sound like one of "those mechanics". Love the truck, just wish it was as simple as my 82 isuzu pup diesel 

Edited October 27, 20186 yr by Moneypit2000