Agreed. Just noting the fact outside those years significant protocol changes were made, pinout changes and some minor hardware changes were made. You're correct in saying that engine controls inputs/outputs remained the same as did most of the logic sensor wise. However there were apps differences, sci vs can, 04.5-05.5 manuals lacked transistors for automatic solenlid controls.
Correct me if I'm wrong. My point is there are stopping points for interchanges between hardware. The ecms in the years noted above have the ability to flash and maintain full functionality with the noted exceptions.
In no way am I indicating switches should be made without a flash update. Quickserve is a great resource when comparing ecm part numbers as well as allowing the user determine supercessions.

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Yes, there differences in the harnesses and some of the peripherals across the years. It is best to match the ECU to the VIN so you don't fight a myriad of problems.

In the OP's case he has the possibility of at least 3 different ECU's in an 04 truck, 2 early and 1 late IIRC. MY04 was a transition year and there were changes in a lot of things. Some ECU ranges will work in others, some won't and that is a bugger to find out at times.

QuickServe to find the matches is a good option for matching. Dealer or a ECU rebuilder is another. Might have to send in the one he has to get the correct one with the VIN programmed in it.

 

ok. that's probably the issue. There was no motor in this truck when he bought it. no ecm also. The 05 ecm came from another truck. so how do I get the vin programmed into this ecm? These are all from a 5.9 common rail diesels not the older 24 valve. just to be clear. I know half way thru 04 they changed motors. That being said the ecm dated 7-16-04 came off of a 05 motor but not this truck. follow? it gets a bit confusing.

 

Whats the build date on the truck in question?

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Ditto, that will tell you what you need to get for the ECU.

The 7-16-05 ECU is an MY05 ECU. MY's run from August of previous year thru Jun of following year. Builds in July are almost always the next MY. Thats why you need the build date of the current truck to know what ECU.

The VIN will tell the dealer or ECU shop which one is needed and what flash to put on it. A lot of this is controlled by the VIB or the truck and not usre they can load the correct programs without it.

 

ok. the build date on the truck just says 7-04. Does that help?

thanks for all the info. you guys are great.

 

I think the build date is the last thing put on the truck so if it is titled as an 04 then you woud need an 04.5 ECU. I don't think the 7/14/04 ECU will work but you could try it with a flash for the VIN of the truck.

Getting that flash is going to be the hard part because not just any place can do it and it MUST be right for the platform. I think the big difference is the APPS, IIRC there is a difference between the output of the engine mounted ones and the cab mounted ones.

 

I think it will work and it should atleast run with a MIL even with the wrong vin.
I think I would be using a scan tool to determine whats next. (7/14 build date should indicate 04.5)
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ok. it's titled as a 05 truck. should we just find a 05 ecm or something? what's the easiest way I guess.

 

While not ideal the ecm with the incorrect vin should still run the truck. I have no idea what implications or other issues it may cause but the truck should still at least fire off. Do you have a scan tool?

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