Odb2 not responding to scanners no start diesel plus it only tries to turn over in neutral?

From the description it sounds like the CM either doesn't have power or it is bad. The security module is in the cluster and if it isn't registering the PCM and that the cluster is active you would get the no start condition because the lift pump wouldn't activate.
What was going on prior to this event?
As a start I would grab a test light and run all of the fuses in the boxes.

https://www.2carpros.com/articles/how-to-check-a-car-fuse
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Replace any bad fuses and try again. Also do a good inspection for any damaged wiring.

Thanks for the info. So, here is what happened: my motor blew up, so I switched the motor out. The motor ran fine, but it had no power, so I took it to a diesel mechanic he told me it was the lift pump. So, I brought it home and put a new lift pump in it did the same thing. It was a new start, but when I left the mechanics, it was running, then all of a sudden it had no start. now I've replaced the CP3 three times I put new injectors I put pretty much the whole fuel rail system brand new in. I'm getting about half a gallon of diesel out of my fast to my CP3 in about 5 seconds, but I'm not getting any diesel out of the CP3 to the fuel rail it's just spitting and sputtering.

And now that I replaced the CP3; my gauges don't move, but my shifter shows what gear I'm going into.

And now that I replaced the CP3 my gages don't move but my shifter shows what gear I'm going into

This is weird, I can plug my scanner into the OBD, and it comes on meaning it's powering my scanner, but it's not scanning anything.

So, it did run but then quit and is a no start. I would really go over the wiring from the engine to the ECM. If you mean you have replaced the engine control module, did you program the replacement so the security system doesn't shut off the main relay?

No, I replaced the motor itself but when I switch the motor out I put the ECU from the new motor in the new truck should I have not done that.

The only thing I've replaced since I got it back from the diesel mechanic was pretty much the whole fuel rail system, nothing else.

The ECU needs to be programmed to match the truck; the engines are both the same year, yes? Dodge changed things multiple times in that time period.

I just put the ECU that was from the truck itself back in still everything is the same I checked all fuses they're none blown.

I don't know if this matters but the 4-wheel service light stays on meaning it says 4 wheel service under the mileage.

So, it is turning over but it won't start, and you are not seeing fuel at the injectors? Have you tried to bleed the fuel system or is that where you say you are getting just spitting? If that is the case, then you are pulling air into the fuel system somewhere or the injector pump has a problem. You should get a steady stream of fuel.

So, I'm getting about a half a gallon from the fast system to the CP3, but from the CP3 to the fuel rail it's only spitting out. I've replaced the CP3 three times all the same results. is there a way to prime the CP3?

The lift pump should prime it. To do that you turn the key on then turn it quickly to start and back to run, that should run the lift pump for about 20 seconds, repeat that a couple times and see if you get fuel from the injector pump.

Tested all fuses getting light to them even the one wire on the OBD but still nothing.

So, the lift pump isn't turning on when you cycle the key? You are seeing nothing when you connect the scan tool? What year is the engine and its ECU and what part number is on the ECU? Did it come out of an automatic transmission truck? Asking because the 2003 is a unicorn, only the 2003 ECU works with the 2003 engine. 02 is different than 04. The engines are also different when it comes to the sensor outputs. I'm wondering if the issue isn't simply parts mismatch.

ECM, 5.9L (RH rear engine), California emissions, (ID 56040477AA)
ECM, 5.9L (RH rear engine), Federal emissions, ID 56028740AB
ECM, 5.9L (RH rear engine), Federal emissions, ID 56040476AB
ECM, 5.9L (diesel), (mounted to side of engine), AT
ECM, 5.9L (diesel), (mounted to side of engine), MT

The 03 ECU is back in the o3 everything from the 03 is in the 03 except the motor block.

Okay, what is the engine itself from? Chrysler made many changes in those years as they were changing corporate bosses. Many of their engines ended up changed in a minor way that made them not interchangeable. The most common changes were to the camshaft and crankshaft reluctor wheels. For instance, on the 3.7 they reversed the direction of the notches on the crankshaft from 1-2-3 to 3-2-1 and the cam wheels got more notches. Everything else stayed the same, the engines looked identical and would interchange fine, but they wouldn't run on the same electronics as they had changed suppliers.
I would hope they didn't do the same with the diesels, but the interchange shows that the 2002 engine is different than the 2003 and the 2004 is different again.
Looking at the individual parts isn't encouraging either, the 2003 cam and ECU only list as 2003. So what year is the bare engine you installed? What parts were moved from the original?

Everything is from a 03 to a 03 it ran before I gave it to the diesel shop then when I picked it up because they told me it was the CP3 it hasn't run since the gages worked and everything until I put 4 different CP3 in it. now no gauges and it will not start.

Here is a video.

Again suggestions.

Okay, if the replacement engine is a 03 it shouldn't be compatibility. I didn't see any tach bounce while you were cranking it. When you turn the key on do the gauges do anything?
If not, then I suspect we are going to need to verify the powers and grounds to the ECU and the dash as a starting point.
Attached are the powers and grounds that feed the ECU. I would check the fusible link that feeds the power to it and make sure it is there.

Can't get my scanner to work on my odb2, plus my gauges don't work when I turn my engine over.

I would first check the fuse #51 in the TIPM for power in the left rear of the engine compartment.

This guide will show you how:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If there is no power, I would replace the TIPM which is easy to do because it-self learns. Here is how that is done in the images below. Please let us know what happens.

I have also seen the cluster cause this issue as well. Can you please check the fuse #51 for power?

It’s very hard to get air out of diesel system I’ve found cracking 1,3,4 injector fuel lines then cranking it (will probably take several times) but eventually does the job then once it starts you can bleed each line out while running to push air out then tighten. Unfortunately, there is no fast easy way of doing it that takes a little time.