Just ran into this on a 2000 1500 5.9

Upon initial key-on all is fine for ~15 seconds, then the odo flashes three times, switches to NO BUS and the CEL comes on.

The truck starts and runs fine but no gauges work.

I'm nowhere near done troubleshooting but so far the following has not worked:
1) unplug ABS module under hood
2 )unplug TPS
3) disconnect, clean and reconnect all three plugs at PCM at firewall
4) bang/press/tap on instrument cluster
5) battery connections look immaculate and truck cranks healthy and headlights are bright, but I guess I could clean terminals just to say I did it

I plan to maybe add a few grounds and continue unplugging every sensor on the bus line to see if I can find what might be pulling it down

 

Check the connectors on the back of the cluster as well. If it runs fine, and just gauges don't work, that's a pretty local problem.

 

Thank you I was thinking this, too. In another DF thread I found from 10+ years ago one guy said he fixed it by just removing the cluster and putting it back in.

 

"no bus" refers to the CCD bus which connects a number of modules, PCM, ABS, airbag module, instrument cluster, central timer module (on higher trim levels), overhead console (if present). Any of these modules can possibly take down the CCD bus, so it could be something else aside from the cluster itself. If you have a diag tool that can read ABS codes see if it still works when the cluster fails. If yes, the bus is ok and you can focus on the cluster. If no, disconnect the other modules.

 

Also, since the truck starts and runs, is it safe to assume the cam and crank sensors are likely not the culprit? Seems to me if cam, it wouldn't start, and if crank it would stall? Oversimplified?

Anyway, I'll see if I can pull PCM codes and I'll try for ABS codes. And then I'll pull the cluster.

 

If it runs good, you can probably exclude most of the engine related sensors, O2 sensors are still a possibility though.