08 LMM Electrical issues, Urgent!

Black2011 · April 3, 2013

I have a 2008 duramax in my possession (friend of mines) and we just put an engine in it. (used engine from a gov't run salvage yard) and upon first start we have several codes and electrical issues. one of which is the batteries die very quickly and the truck with attempt to crank, followed by the dash lights flickering and dimming, and the fuel level gauge jumps up and down. I will take a clip of the lovely events later.

I will also record the codes, but for now I have

U0101- Loss of communication with PCM

P0118-coolant temp circuit high input.

P0206-inj 6 open or poor connection

P0207-inj 7 open or poor connection

and also the codes for inj 1+4 but cant remember the #'s

im getting a new set of batteries today to see if it helps.

Any advise is good.

I have checked fuses (all OK) and battery cables routed properly. (all OK)

however when we first hooked up the batterys my helper had hooked the positive cable for the intake heater to the manifold, which im sure wreaked havoc on the batteries.

update tonight with vid and code info.

Black2011 · April 4, 2013

Ok well here was my Issue. Low power, message for "engine power is reduced"

I should mention this truck is deleted, No DPF on it. Programmed with PPE handheld programmer.

I found the issue for low power. ( I originally thought someone had stuffed a rag in the turbo and when we put the piping on we didn't notice) however the problem was a bad engine harness connection. ( also the cause of the coolant temp code, injector codes and inoperative coolant temp guage)

the truck has oodles of power now. Still no 4wd though. we didn't have anything in the trans/transfer case area unhooked though...

SouthCo · April 4, 2013

Glad u are figuring it out but what happened that an 08 duramax needed a new motor?

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Black2011 · April 4, 2013

Glad u are figuring it out but what happened that an 08 duramax needed a new motor? Sent using Tapatalk

200K miles, crank broke. Prior owner claimed it "ran when I parked it, but had a knock" most likely a lack of maintenance and abuse. (engine would not turn over. cyl 5+6 rods were jammed into the block, we could not pry them away with a large bar) we were forced to cut the pan off, then cut the crankshaft closer to the rear and then we could remove the torque converter and flex plate.

This is the second 200K mile duramax I've changed in my shop at home this year.

Anyone have ideas for the 4X4 issue? the shifter doesn't display anything. (shift on the fly)

Black2011 · April 4, 2013

also service trailer brake message on

gmtech4 · April 4, 2013

scanner reveals all ailments.......no really ,,,it does

Black2011 · April 4, 2013

I have a generic scanner. It does not read gm chassis codes. just ecm codes. no codes in ecm, no MIL on. any idea what causes the 4wd shifter not to work? (IE the lights don't even come on?) Im going to take a look underneath today to see if somethings obvious. hopefully a test drive will sort some things out (abs light on)

gmtech4 · April 5, 2013

you have a code in the TCCM

you also have a code in your ABS

needs to be scanned with a real scanner

Black2011 · April 11, 2013

ABS light went out when we were driving it. gave it back to the owner, hes gonna have someone with better equipment check it out. (rather than me play a guessing game and throw parts at it)

Thanks for the replies!