Help PLEASE

[anto3]

I have a 2004 c4500 with a 6.6. No Eng light on at Key on Eng Off. it does not crank and No Communication To engine side. I can Communicate with trans and body. Some one had mentioned to me that my ECM is locked.
And said that I should disconnect the Batteries, connect the positive cable to the negitive cable for 4 hours and it will unlock it.
Can someone tell me if this will unlock the engine side

 

[bluecollar]

Check the ecm fuse?

 

[anto3]

all fuses and relays are good
Thank You

 

[bluecollar]

Was something done that could of messed up the ecm? Reflashed?

 

[anto3]

did a little bit of body work and repaired fuel Gauge . NO WELDING

 

[bluecollar]

Anywhere u coulda forgot a ground? Didnt know if u mean fenders off kinda body work.. U can attach a ground wire directly to ecm to rule that i believe..

 

[anto3]

BYPASS All grounds? and ground ecm directly to truck?

 

[bluecollar]

No just attach a ground directly to the ecm just to rule out ur ecm being grounded.

 

[anto3]

I will try and let you Know.
THANK YOU

 

[bluecollar]

Good luck hopefully someone that knows more will help. . This is just from my fair share of electrical problems

 

[anto3]

Yes they can be a nightmare

 

[anto3]

No luck at all I AM READY to disconnect all 3 batteries, and connect the POS and NEG
Batterys to try to unlock the ecm