I’ll try to keep this short and answer questions and/or suggestions. A couple days ago in our 2010 suburban, turn the key and nothing happened. Open the hood, check connections and try to jump the battery. Nothing. Put the code reader on and get a U0100 code - can’t communicate with the ECU. Check all the fuses and relays. Everything is good. Do some research and I’m thinking starter. There is a video online saying the starter sometimes causes this issue and it seemed like a starter issue. I take the starter off (not as easy as Youtube makes it look) and run up to Autozone. They test it say the starter is bad! I get the new one installed and there is no change. Battery is still fully charged and everything else works but the car won’t start. I replace the ECU and still no change. Exactly the same - turn the key and nothing. No click, no turnover, no nothing. I’m
now thinking it has to be wiring. Any ideas? How do you troubleshoot the issue using to isolate an issue? And then how do you resolve it? I did test the can bus and appear to be getting a bad reading (128 ohms rather than 60 they say I should get). Help please.

 

I just found my issue. Wire have been chewed up right at the firewall. Now trying to resolve that issue.

 

Thanks for posting this. Was it a rat or just worn out? Driver or Passenger side? I'm having a similar issue and gearing ups o test.

 

It was definitely a rodent. I assume it was a rat but I never actually saw it. I ended up splicing all the wires back together (7 that I found) and it has been working since. The fuel gauge isn’t reading but I can’t find another broken wire. I’m guessing coincidental, but who knows. The car runs well and there are ways around the fuel gauge issue.

 

I had a similar problem with my 2010 Suburban 2500. I tested the batteries (dual) and the alternator. Both were ok. I tested the ground and positive wires. Both ok. Before going deeper, I took off the positive and negative battery cables and cleaned the mounts and the posts thoroughly. That fixed everything!