I've seen several issues on here with my problem, but everyone seems to have different solutions.

My van was running fine, then one morning I got in it, drove about 20 feet and it stopped. Had to push it back into the driveway. The "No Bus" came up on the odometer, no position for my transmission was shown. The fuel guage was below empty, as if it was not powered up. The other three guages basically at zero too.

I figured I had a problem with the fuel pump, and sort of had been thinking I wanted to drop the tank and check it anyway... so I proceeded to do this. I decided to just replace the fuel pump due to its age and the fact that the filter is part of it.

Once in, I started the van and drove around the block. Figured problem cured.

The next morning I went to start it and it would not start. I checked for power at the fuel pump connector and had none going to the pump.

Since then, I have replaced my battery (which was due beings it was the original one that came with the van) and got a rebuilt PCM (mostly because of this site and how that seems to be the main cause). NO luck.

I will point out that the van has started several times since this began three weeks ago. I haven't really moved the van since that drive around the block because when it does start it has stopped within a minute.

I can check the van in the morning and it will not start (I know because the gas guage is below zero)... and then I can check it in the afternoon and the thing starts right up (very frustrating). It is my work van and I am tired of using my family car for work.

I have bought the original service manual, which has helped me understand several things... but what it does not show is the PCM's programming. I am an electrician...and can follow prints. To get an error code of 920, 921 and 999 the program looks for XXX inputs, must do some comparisions... and if it does not see what it likes, it produces an error code. From the manual, all it says it that it is missing the speed signal and the distance signal from the PCM to the cluster. If I read the manual correctly, the speed signal leaves the PCM at B27 on C3... becoming wire G7... which is white with an orange stripe.

What it doesn't tell me is what type of a signal this is and can it be measured with a volt meter? And what exactly does the program look at to send this signal off?

I have been removing one sensor at a time for a while now with little luck. Sadly, every so often I may be touching a sensor and here something click by the dash... and I look up and see the gas guage has a reading. Of course, the van starts and I know longer have a problem. But it is definately not reliable. The next time the van is not working I try the same sensor thing with no luck.

Would love some thoughts on what exactly to check. Anyone know where you might be able to see the PCM programming?

 

As one to another, either your ASD relay, or your PCM is shot. Considering the No Bus message you're getting, I'd say it's the PCM.

I just helped someone else solve this same problem. The way I had him confirm it was the PCM is; the next morning that it doesn't start, warm up the PCM with a hairdryer, (make it warm not hot). If the engine starts up with the PCM warmed up then the PCM is the problem.

Here's the link to the thread I mentioned above: https://dodgeforum.com/forum/dodge-r...e-morning.html

 

The funny thing is that I DID just replace the PCM with a rebuilt one from what looks to be a reputable company, with the same results. During this mornings trial and tribulations, I switched back to my original PCM with no better results then stopped to do some more research.

However, after I posted my first comment I went out and was checking sensors... and wouldn't you know it the engine started right up. I find myself just standing there shaking my head.

So... I put in my new rebuilt PCM... and the van would not start. The old one was put back in and it again started... so now I am thinking it could be the PCM and I just got a rebuilt one that was not programmed correctly and will be checking with the company to find out if we can replace this one.

Thanks for the tip... if tomorrow morning it does not start, I shall try to give the PCM a perm and see if that helps!

I also had already swapped out the ASD relay so that component has been eliminated.

 

Well if swapping out a component eliminates it as a possibility, then by that same rationale your PCM isn't the problem.

 

I see your point alloro, but my one line comment obviously doesn't include the entire process I did to eliminate the ASD relay. I was absolutely positive that the relay itself was not the fault - which of course does not rule out the socket itself...

In any case, the weather has been warm the last couple days and during daylight hours my old PCM has not failed. I swapped out between my new rebuilt one and my original one... and only with the original one would my van start. This evening I went out and tried it again - with my old PCM in place, and it did fail to start. Who would have thought I would have been excited to see this. So I grabbed my wife's hair dryer and set the ignition to the on position and proceeded to "warm" up the PCM. Within 3 minutes I heard some DING DING's inside the cab... I went and checked, and sure enough my gas guage and such were showing life. I turned the key and it started up.

Thanks alloro, it makes me feel much better knowing I didn't mis-diagnosis this thing and the rebuilt one is bad. I have already sent them an email and have boxed up theirs to return it to them. Hopefully the next one they send will actually work.

 

Following your helpful threads I see this has happened to many other people in many makes and models of cars. I'm driving down Ventura Blvd and the van dies. I muscle it into a parking spot. On the odometer I see "No Bus." I crank it over and it sounds like no fuel even though the meter shows a third of a tank. I get a ride to Kmart for a gas can and dump a couple of gallons into the tank. Still nothing. The engine turns over but won't start. I call my guy (maybe the wrong guy for the job). He does precision allignment and is generally a good wrench but here's the story: have it towed to his shop, he thinks it's the fuel pump, drops the tank, tests the pump, then replaces it. Puts the the tank and gas back, fires the engine and it runs for ten minutes. Engine stops so he orders another fuel pump. Now he's having a bad day. Installs the second pump, fires the engine and it runs for a minute then dies. Starts testing relays and calls in a guy with a diagnostic machine to test the PCM. This started one week ago today. I sure hate to have it towed as a basket case to another mechanic because who doesn't hate this? Any advice? Thank you.

 

At this point I would wait for the results of the PCM test. Most likely the test is going to find a problem with it.

 

Right. I went to visit the van today and no new news. I told him about the hairdryer idea. He said he just might try it. I'll let you know how it turns out. I just want back my rig and I want it to be as reliable for the next 90,000 miles, as it has been so far. My wife is worried though that it has reached the point of nickel and dimes out the door from here on out. Hope not. Thanks again.

 

I'm still waiting for the replacement PCM... and with a week long vacation planned next week, looks like it will be another week before I find out if a new PCM does the trick.

I was talking to a friend of mine and told him about the hair dryer trick... and he had the perfect answer for my situation. He told me to load my portable generator into my van and take a hair dryer with me. Hmmm... I wonder how long/far the PCM would go on a hair dryer warm up.

 

Probably far since the engine heat will keep the PCM warm once it's running.