I have been hammering the search here, and on the Google, for weeks now trying to get a handle on this 'no bus' / 'ccd' error my RAM has been exhibiting. Lots of good info out there, but very little relating to the V10 specifically.

I've swapped my PCM into a friends RAM and confirmed that my PCM is fine. I've since tried unplugging everything at the transmission (reverse/neutral switch and PCM plug), the IAC, the TPS, the cam and crank sensors, as well as the oil pressure switch hoping that one of them may have been shorted. None of them have made a difference. Every so often, I'll get gauges with no error on the dash or trip computer, but the fuel pump only intermittently runs as though it has a bad connection (you can hear the relay going bonkers). I've swapped out the relay to no effect, and even jumped the pump to be sure it works ok (runs perfectly fine when jumped at the relay). I've been through the fuse block under the hood more times than I care to count, and I've gone over the big harness plug under the dash.... nothing seems out of the ordinary.

I've also checked the ground straps I could see on the firewall and confirmed that the PCM has a good ground.

At this point I'm at a total loss as to what the hell is going on with this thing. I parked it about 3 months ago and it was running great. Come out to move it and this is what I have now. When I first confirmed that the PCM wasn't at fault, I was happy that I wouldn't have to spend ~$400.00 on a replacement (and have to deal with getting my SCT tuner remarried to a new PCM). But at this point, it'd be worth $400 to get the thing working!

Anyone have any thoughts?

 

I had the same problem with my ram awhile ago, I took it to the dealership and they said it was from rain coming in by the cowl. the rubber part above the cowl that acts as a seal wasn't there so during the extended rain storms here water got in and burned a fuse out. so they replaced the fuse and put the rubber part in and no more problems.

 

I wish it was just a fuse!

I've gone over every fuse and relay in the system, including all the ground straps I could find under the cowl at the firewall.

I'd rather have a rod sticking out the side of the block - THAT I can fix!!

 

Does the truck have wacky gauge readings in reference to the speedometer, tachometer, fuel level gauge, temperature gauge, oil pressure gauge, etc?

I have had the no bus issue before and it was a result of the connection to my instrument cluster losing continuity. Problem comes and goes, and normally goes away from the light tapping I deliver to the face of my instrument cluster.

The truck, when this issue arose however, did still run. The gauges just went all wacky. It could be that the the instrument cluster itself is on its way out, or the connection to the instrument cluster is going out through the wiring or otherwise the wire's terminals.

I have no idea on how to test the instrument cluster's reliability but if tapping on it seems to help, you might want to consider checking that area and verifying that all of your connections are as tight as they possibly could be.

 

The instrument cluster is dead - as in, no readings at all. It does, however, pass a self diagnostic test. When I get a momentary connection and the CCD / No Bus goes away, the gauges work properly and I can see voltage, and fuel level. When the error message appears in the mileage display and on the trip computer, everything is zero.

 

Remove the cluster and inspect and clean the connection on the back of it. As stated, it could be the problem. And please remember to disconnect the neg battery cable before doing so.

 

For anyone interested, I found the problem with my issue.

Everything pointed to something on the 5 volt circuit. The 5 volt circuit is the sensor circuit (TPS, IAC, MAP, Crank, Cam and transmission) and after going over every inch of this, I was at a dead end. I broke down and spend the money to talk to a Dodge tech on Justanswer and he pointed me to the 2.5 volt circuit. The 2.5 volt circuit contains the ABS, Airbag, CTM (Central Timer Module), Overhead Console, Radio and PCM. After going over all of these modules and having everything check out, all signs kept pointing to the PCM, which I knew was good as I installed it in my buddy's '01 and it worked perfectly.

Sooo, with the new information I got from Justanswer, I was able to do a better Google search and got a hit on a Jeep forum that sounded identical to mine. In that thread the OP had the same problems, more or less did the same things I did, but found that a pin in one of the PCM plugs was corroded. Specifically, pin A22 (Plug A/pin 22). Now I had already checked my plugs, but having some information about which ones provided power to the PCM (and what values), I grabbed my DVM and went about checking mine. Everything was OK until I got to pin A22. A22 is supposed to provide a constant (non-keyed) 12 v source to the PCM. Mine was all over the place, from 400 Mv, to 12.4 v. I even back probed about an inch to be sure it was't the pin itself and was still getting the weird voltages.

So I went about finding where this wire terminated and was able to confirm that it was being fed 12 volts, but at some point from the junction in the fuse box under the hood, to the PCM plug, I was losing continuity. Anyway, I wanted to confirm my findings so I went about splicing in a new wire. When I got to the PCM connector, I pulled the wire loom back about 4 inches to get a decent bit of known good wire to splice into and I found the break. A small section of the wire was swollen. I pulled on it a bit and it broke in two, exposing a bunch of green, corroded copper wire fragments!

Needless to say, I spliced in the new wire, connected everything up and the truck fired up instantly!

All along I figured it was a problem with resistance/connectivity somewhere - I just assumed it would be a ground hidden somewhere and corroded from exposure. I've never seen a wire corroded *inside* the insulation so far away from an exposed connector like this.

Oh well, it feels good to drive the 'beast' again, after almost a year sitting in my yard!

 

Wow, nice job staying with it till you found the issue. And thanks for replying with the fix so others here can find this in a search.

 

+1... Case closed