Ficm electrical issue any input

slor1de

slor1de

Member
Have an 05 lly cab chassis zf6 truck. Blew the edu fuse. Had wires rubbed thru on driverside connector at valve cover, harness smelled of burnt wires. Replace harness with new GM engine harness. Truck is not blowing edu fuse after harness install and will start and run. Throwing u0105 and u0073, have power and ground at ficm connector. Truck doesnt seem to be firing on #3,5,8 cylinders, Makes no difference when killing injectors with scanner on 3,5,8. Builds and carries desired rail pressue, balance on 3,5,8 is higher that the rest.

Anyone have any input. Feel this is 100% electrical. Like to try a ficm, but sounds like there failure is rare. (Any way to test the ficm). This truck was running fine all day, shut off for lunch, this happend when attempting to start afterward. 250k mile truck bone stock with 30k mile on a jasper long block and 8-10k mile on complete new fuel system from sending unit,filterhead,cp3, and injectors.
 
You'll have much better luck with the guys on DuramaxDiesels.com

The FICM is rare to have problems, but it happens. IIRC, when it sees a short or loss of connection to one injector the whole bank will shut down. Maybe double check your injector plugs, and look into the icepick fix.

But based on what happened, I'd say the harness shorted out and toasted the FICM. If the harness is new, and connections are good, there's no reason for it to throw those communication codes.
 
Jwhite
Harness is new GM. Have been over the connections a few times, will check again . I agree the ficm failure is rare. I feel the shorted harness got the ficm.
 
So Cyl 2 does fine? 2,3,5,8 are bank 2. but typically if one goes down or has a poor connection it will shut the bank off if its an electrical issue between the ficm and injector.
 
Mudn
Yes, its just 3,5,8
I think a got another ficm lined up to try begining of the week. Hopefully that will fix or rule out the ficm
 
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