About a month ago, after driving a few miles the van died, I pulled over and it wouldn't start.
I then noticed the odometer said "No Bus" and the gauges were all flat. After about 5-10 minutes of sitting there, the gauges went back up and the message disappeared and I was able to drive another half mile and it happened again.
Got it towed to the station, they looked at it and for $100 told me it needed a new computer but I had to go to the dealership for it because they can't program it.
I came to pick it up and put the key in and the ASD relay was clicking. I pushed on it with my finger and it stopped clicking, and then the No Bus message went away. I was able to drive the van about a mile home at this point. I thought maybe this had fixed it so I took it out for a drive, and it worked fine for about 15 miles, at which point the same No Bus and the van died.
Got towed home again which is where the van is now. (While waiting for the tow truck I had the radio on and the door open, and the battery died after about 30 minutes.)
So I charged the battery and the van was able to start, I let it run about 20 minutes and it stalled and had the No Bus message again.
Since then, tried disconnecting the crank and cam position, throttle, MAP, governor pressure sensors and still have No Bus on the odometer. I measure the voltage on each of these to approx. 5 volts.
I ordered a remanufactured programmed PCM, and put that in but I get the same No Bus message with that, so I put the old one back in.
I am from time to time able to get the van to start for a few minutes, but it always dies within 30 minutes.

Any ideas as to what else to try here?
Could the problem with the new PCM be that it isn't programmed with the VIN and mileage yet? From what I've read that shouldn't matter.

 

Another note, sometimes after hooking the battery back up or after charging it, the ASD relay and the unlabeled relay in the junction block both start clicking. Does anyone know what the relay at the bottom on the junction block is?

 

In the bottom of the fuse block in the side of the dash, as you are looking at it, standing in the drivers door. On the lower left, is the flasher relay, immediately above it, is the relay for the heated seats. The two circuit breakers to the right of those, are for power windows/locks. One of them clicking indicates a low voltage condition. (or, your emergency flashers/turn signal is on...... )

No bus is a fun one to figure out. Basically, what that means is, the cluster has lost communication with the central timer module. Given that the truck stalls.... seems the computer is losing one of the inputs it REALLY likes to have, and gets annoyed.

Get it to fail, and then see what's missing. Does the fuel pump prime? Are you getting power to the coil while cranking? Getting spark at the plugs? Injector pulse? Find out what is missing, and you probably find your problem as well.

Welcome to DF!

 

2001 Ram Van should be in the Ram Van section. I would add to inspect the PCM connector. The locks inside the connector will break and allow the wire to pull back to loose contact.

 

First, sorry this is in the wrong sub-forum, can someone move it?

After checking all kinds of things I had the van towed to Dodge dealship to see if programming the PCM would fix it since I had called to ask them and they said unless it's programmed it won't work.
Once I got it there they called me and said that they couldn't program the computer because they use the bus to program it so they need to figure out the problem there before they can program it. The next day they called and said it was fixed and they had programmed the PCM. I asked if the no bus message was gone and the service manager said he didn't know but the van was running. I explained to him that it does periodically start, but after running for about 20 minutes it would die and not start again (which I had told them when I had it brought in). He said they'd try that, and the next day when I called he said the problem was still there and that their diagnostics told them it needed a new central timing module. The thing is this van doesn't have a central timing module, it has the keyless entry module in it's place. I asked him that and he said that's what he means.
Now, the problem is that Dodge no longer makes that part. I spend a few hours at junkyards today but didn't find one, and haven't been able to find one online. The dealer can't tell me what year and model Ram trucks/vans would use the same part so I looked through a bunch, and most had the CTM.
I also haven't been able to find the part online anywhere (I don't have the part number with me, but I know it's AB at then end).

So my question is, would this module really cause a no bus message and cause the van to not run? From looking at the service manual it doesn't even appear to be connected to the bus at all. Second, if this really could cause this problem, where can I get one?

 

Honestly, might be really stupid, go to the van, pop the cover off the PDC and tighten the big screw down closer to the motor. That cured this problem on my truck. My 2 cents.

Im not sure on the CTM issue.

 

So far as I know, your truck should indeed have the central timer module. Keyless entry is a part of the "highline" version of it.

That said, even if it failed, the van should still run......

So, what seems to be happening is, something is getting hot, and failing. Which in turn REALLY annoys the PCM. (it might BE the PCM that is the problem....) The No Bus message just means the cluster has lost communications with the CTM. It's not really a critical failure...... (aside from not having a clue what anything is doing.....)

Where did you get the replacement PCM from?

PCM not being programmed will still run the van, it will just have the ABS, and Air Bag lites on, as the VIN doesn't match.

 

There is no central timing module in the Van midline version, it just has the keyless entry. But anyway, they still get the No Bus message with the keyless entry module disconnected, and I found the only reason they thought that was the problem is that they unplugged it and it worked. Of course, when they tried again later it didn't work so this was just one of the times every so often that it does work.
The dealer wanted to charge me $95 an hour to diagnose it and didn't have an idea of how long it would take, and seeing that they had told me it was the keyless entry module that according to the schematic isn't even connected to the bus I didn't really trust they would be able to figure it out so I took it to another local mechanic.
After they looked at it they told me there is a short in the instrument cluster, and if they can fix it would cost $450, or $600 for a new one. They also said there is a problem with both PCMs (the one that was already in there and the remanufactured Cardone one I have), and that I should get a new one from the dealer for $800.
They say I can't use an instrument cluster from a junkyard because it won't have the VIN and mileage programmed. Does anyone know if this is true? Can I buy one and put it in and if that is the issue will the No Bus message go away? Or do I really need to spend $450-600?

 

I would have to see the service manual to make a judgement on any of that. Without wiring diagrams to look at, and see how communications are supposed to work..... anything would just be a wild guess, and probably wrong. I am rather curious why chrysler, in their infinite wisdom..... would use a completely different system for essentially the same drivetrain, just in a different body.