FICM's swappable?
- Thread starter PAT
- Start date
yay
The communication Style is different. If you use an lb7 FICM in an 05 truck it will not work. If you use an lb7 FICM on an LLY engine in an 01-02 LB7 truck it will work. The LLY FICM will not work on an LLY in an 01-02 Lb7 truck, using the Lb7 controls. The inlet/outlet ports are in different areas as well. The pinout is identicle on both units.
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There was a discussion in the I've seen the impossible I believe thread about converting a LB7 to a LLY to rid the injector failure issue in the LB7.
Have you tried this Russ? when we did my harness, Ben decided that the databus was just labeled differently, but that the signal was identical.
Yeah, I couldn't get it to work either (LLY FICM, on an LLY engine, in an 01-02). Swaped in the LB7 FICM, and she fired right up. As you know, that swap is fun tuning wise lol. It took a bunch of trial and error to get a good solid "base" tune.
I guess it is useless. I didn't try it because we had already made the new harness by the time we did any looking into the Data Bus itself. We didn't see any reason it wouldn't work on paper...but if people have tried it and it hasn't worked...then it doesn't work. I don't know if all things were equal in these other attempts.
If your getting a U105 code check all your grounds. There is one on the front crossmember and one under the drivers door side. I went through heck with mine until I pulled up a TSB, and cleaned my grounds. The dealer couldn't even fix it.
They should be darn near dime a dozen from salvage as they are not prone to fail. I have a brand new one here that should be LLY that was ordered by mistake.
so did you try the grounds? The dealer changed my ficm and ecm and changed them back to no avail. The grounds have to be super clean.
Didn't change them. But I added another and ran it to a ground on the truck as well as trying it to the ground on the battery.