I got a guy that has been in touch with me by email and been trying to figure out his CCD Bus problems. So far nothing I suggested works. Currently he can see the 2.5 and 2.4 vold bias voltage at the OBDII port he's only got the ECM and PCM plugged in to the bus all other modules (Radio, ABS, AirBag, etc.) are unplugged to try and isolate the problem. But still it will not communicate... The engine will start and run... Tachometer functions but all other gauges are dead. No AirBag or ABS lights... But unable to read error codes at all. I'm hoping one of you might have an idea...

From experience if the dash was pulled back for some reason I have seen the wire connections come loose behind gauge cluster and cause similar issues. Make sure everything is plugged in tight. If things were messed with look very closely at every single plug and make sure the pins and sockets are fully inserted into the plastic connectors. Many many times I have seen a single pin get pushed out when connecting a connector together. Especially if people go prodding around with a DVM they push the pins and sockets out when checking voltages if they try and intert the leads too hard. Also have seen people stretch the sockets out with the DVM lead and the pin will not make contact when plugged back together.People need to be taught to check wires for voltage ohms ect from the back side of the connectors where the wires go into the connector and not the front face where the pins and connectors are. In diesel school to teach us lessons on this the instructors would put clear nail polish on the connector pins and sockest so it would make you test them from the back side otherwise you would get no reading from the front as it was coated with a clear coating that couldn't be seen thus a lesson to check all scenarios when it comes to electrical troubleshooting.

Any new developments?

Well he's taken a PCM from another dodge truck (gasser) and hooked it up and the fuel gauge and one other gauge came back to functional but still got a No BUS message... I'm starting to wonder if the PCM is truely bad...