Code 900, The CCD data bus is not operational: check the CCD data bus connections at the cluster, check the cluster fuses, check the CCD data bus bias, check the CCD data bus voltage, check the CCD data bus terminations.

Code 920, The cluster is not receiving a vehicle speed message from the PCM:

Code 921, The cluster is not receiving a distance pulse message from the PCM:

Code 940, The cluster is not receiving an airbag lamp-on message from the ACM:

Code 950, The cluster is not receiving an ABS lamp-on message from the CAB:

Code 999, An error has been discovered:

this is what I found

 

thanks for all the help
installed new 3rd ligt (LED)
I still no bus still starts and runs
my smarty still connects (set at stock) -edge complete disconnect- also was not showing connect when connected
I was getting abs light before this start for several months and When I release the parking, the "brake" light stays on.
how to test cluster?
I'am thinking of doing new dash... my heater core is out also...

 

still nothing
cleaned the plug under the drivers floorboard
rocked the cluster right side turn off and on comes back no bus
left side nothing happens
how do I know if pcm or ecm??
thank you

 

stil nada!
replaced abs module/ speed sensor /ecm and the cluster/ tested all fuses and relays
so frustrating!!!

 

I've been having the same exact problems...same codes, no gauges after a few seconds of working, ABS light on for a while beforehand, everything. My truck ran fine for a while with no gauges, and then one day I got a VP44 p0126 code and now it's driving terribly/smoking. Re did the grounds, and am about to send PCM and ECM off.

You can test the PCM ground take the connecter closest to the driver's side off, and continuity test pin 31 to the ground on the fender next to the passenger battery. 10 ohms or less means bad PCM, higher than 300 ohms means bad ground. Mine was .1 ohms which means bad PCM. Already sent it off to one shop and they said the PCM was good, but I don't believe that so I'm trying again, along with the ECM. To me, the delay in the gauges working is a bad component on some board, somewhere.

Re-do your grounds per the thread below to eliminate ac noise and any questions of bad grounds. I did mine tonight and it didn't help, so I really think PCM is fried.

https://mopar1973man.com/cummins/art...mplified-r574/