No Start U0105

[fast03]

Hey all, I got a buddy with an 04.5lly having a no start with this code. Truck runs a 50hp tow tune and is basically stock otherwise. He said it started having a high and low idle. then he shut it off. It sat overnight and will not restart now. I have had him check all his wiring from the ecm to the FICM. He says he cannot find any chaffing or breaks and that all the connectors are tight. Any ideas?

 

[gmduramax]

Unplug the connectors on top of the motor and plug them back in.

 

[fast03]

Unplug the connectors on top of the motor and plug them back in.

He says he tried this. He claims to have gone through everything.

 

[gmduramax]

U0105 is the FICM right? I had an 04 that was parked and the next day it wouldn't fire. That fixed it. Do you have an FICM he can swap in to see if it's bad?

 

[fast03]

U0105 is the FICM right? I had an 04 that was parked and the next day it wouldn't fire. That fixed it. Do you have an FICM he can swap in to see if it's bad?

He is going to try to find one. He is in an Diego and I am in L.A. Lots of phone calls.

 

[fast03]

Can a bad CP3 cause this "Lost communication" code?

 

[fast03]

does ficm or ecm control cp3 at all or is cp3 only mechanical? ie: if ficm or ecm is bad would we still see flow from cp3 while cranking?

 

[gmduramax]

I don't think the cp3 would cause any loss of communication. If you unplug the FPR the CP3 is mechanical and will make max pressure

 

[fast03]

Thanks

 

[fast03]

Update is that the cp3 flows fuel.. so likely still bad wire or bad FICM?

 

[fast03]

So my buddy swapped out the FICM from another friends lly and the truck started right up. Don't really hear about FICM's going bad.