My husband and his brother are working on a 2001 Dodge Ram 1500 Van, 6 cylinder 3.8L. It was hit while parked in a hit and run accident in April of 2022 and has been having issues since. It wouldnt start after the accident and we found out the PCM was damaged, replaced it, jumped it and it worked just fine for about a week before dying out completely. Turns out the starter was bad too because it wasn't cranking/turning over. Replaced that and it will crank now but no start and still NoBUS. We replaced the MAP sensor, the throttle control sensor, and the Crankshaft Position sensor and still no luck.

They just recently replaced the fuel pump because it wouldn't prime when the key was turned, and even with this new one it still will not prime. It will prime when bypassing the PCM but not when plugged in. Is this where our NoBUS issue is? Bad wiring between the PCM and Fuel Pump?

Fuel tank is also somewhat low because of having to replace the Fuel pump, is the tank just not full enough to prime properly since the van is on a slope? This van is my husband's baby and I wanna try and get answers to help him out.

 

I'm just going to put out a generic idea .... I know most vehicles have a built in safety feature. If they are involved in a accident, there is a relay that will trip upon impact and shut off the fuel pump. So it is not pumping fuel and create a fire.
Typically there are several various relays next to the pcm and possible this relay is there also ....

This makes sense knowing the pcm was damaged and needed replaced ..... Running for a week afterwards makes no sense if it was this relay.
Unless it was just damaged, never tripped until a week later.

So that is the only idea I have, check the wiring schematic for the fuel system and locate the relay .....

 

Where was the van hit? How bad??

If the pump doesn't prime at initial key on..... have you verified all the fuses are good??

 

It was hit right on the rear end, bent in the entire bumper and back double door under the back passenger tail light. They worked on it yesterday, they bypassed the PCM with wiring and confirmed that it is one of the 5v sensors that's not communicating. When bypassed, the engine will now start but runs extremely rough, and will die out when they let off the throttle. What's the best way to test each sensor rather than just bypassing them all?

we changed the spark plugs about a month ago and tested them all yesterday, vehicle is getting spark. We will be replacing fuel injectors and cleaning the throttle body, as there is a buildup from old fuel from sitting for as long as it did.

 

The NoBUS message is telling you there is a loss of communication between the PCM and the instrument cluster. Yes, it could be the wiring, such as the 5V sensor supply shorting to ground, or it could be a failed instrument cluster. There is also a possibility the ASD relay is bad. The ignition switch powers the ASD relay, which in turn powers up the PCM and the fuel pump.

There is a test procedure for the instrument cluster so that you can see if all of the bulbs and gauges work. With the key off, press and hold the odometer reset button while turning the key to the ON, not start position. Once things start to happen...release the odometer button and watch the show. If for example the fuel gauge isn't working, but works during the test, the wires running to the fuel level sender in the fuel tank could be what is shorting to ground, as a result of the damage back there.

 

I didn't know about the odometer test thing! I will definitely let them know on that one to try and identify where that short is.

 

@alloro ASD (automatic shutdown relay) .... thats the one I was trying to think of last night.

I just remember a story of a friend had to tow a motorhome in off the freeway.
The motor home was traveling on the freeway and a small piece of plywood lying in the road was uplifted by air of a semi truck passing over it and it hit the motor home in the grill.
They continued on and it died about 1 mile down the road.

There was no body damage on the motor home, the impact was enough to set off the ASD ..... Why I would definitely be checking it was working.

 

There is a sticky thread up top on this forum's main page that has some ASD conversation which may or may not be of help. It is an older thread and some of the pictures are no longer available, but all of the text is.

You can also click this link to access the thread.
ASD Relay Internals - DodgeForum.com