LLY No Crank, No Communication after unhooking batteries

[dtreid]

Had the bright idea to clean a corroded positive battery connection.
Removed neg cables, cleaned dirty positive and put things back together.

Now no crank, no communication with scanner, fuel gauge reads empty.

Cleaned all the grounds. Checked all fuses. Notice I'm not getting power to edu fuses when key on.

Really driving me crazy.

Wondering if I fried the ecm?

Any suggestions. I need the truck back!

 

[2004LB7]

check the 175 amp mega fuse

 

[dtreid]

Mega fuse is good

 

[dndj]

There should be only one EDU fuse, 25A. The EDU fuse (aka FICM fuse) is fed power through the EDU relay (aka the FICM relay). Power for the relay coil comes through the PCM B fuse, which is always +12v hot (not switched).

No power to the EDU fuse when cranking may be a symptom of deeper troubles, because the ECM is responsible for energizing the EDU relay (grounding the relay coil). The ECM also monitors this circuit through the ECMRPCV 15A fuse.

 

[dtreid]

Does anyone have a pinput for the ecm harnesses? I have a spare ecm. Can I just plug it in and have it start or do I need to have it programmed?

 

[2004LB7]

if it's new or a blank ECM then you'll need to take it to the dealership or someone with the tools to flash the stock operating system. if it is already programmed then you need to adjust the vin to match or do a VATs relearn to get it to start

 

[2004LB7]

 

[2004LB7]

have you tried disconnecting both batteries and waiting a few minutes then reconnect? battery voltage good?

 

[dtreid]

I've left them disconnected overnight. Good batteries.

 

[2004LB7]

sounds like a bad fuse or fried ECM then. I'd verify the power and grounds at the ECM connectors as posted above. if that all checks out then probably ECM

 

[dtreid]

Problem was a bad ecm. Put a replacement in and we're back to normal

 

[dtreid]

Problem was a bad ecm. Back to normal with a new one installed

 

[dndj]

Bummer about the ECM. Thanks for reporting back.

 

[dtreid]

Not sure why it fried by just unhooking batteries. Perhaps my bad connection on the one battery caused a voltage issue that was hard on it.