what i n the world is diagnosis code UO100? I will tell the weird story later, but what does it mean on a 04 srx v8 awd? 62000 mi.

UO100: You owe $100.

Actually, I have no idea, but just HAD do say it! :)

Loss of comunications with ECM. Usually a meaningless code.

OK good then. Long story LONG!

Ok, i'm washing the car today by hand and I guess I had a door open too long and it drained the battery. No problem, I have a jump box. Well that wasn't fully charged, and on top of that the car locked itself the moment the jumpbox was connected to the battery. Some sort of anti theft function. Now keys are locked into the car on top of car being dead. I call roadside assistance for a unlock and jump. They come out and unlock it very easily, but when it is time to jump it, it won't start. The key also wont release from the ignition either. I am pissed and trying to figure it out like the locksmith is. Go to the trusty manual and find the ignition release instructions. There is a little button under the column that you have to unscrew and push in on with a toothpick to release the key. Car finally started and this code shows up. I take it to autozone to check it, and they have never seen it before. Guy thinks it might have something to do with the brakes(thus my frantic plea) and when I get home the left rear "tire shock area" is making a sustained buzzing sound when I got out of the car which further freaked me out cause I thought something had gone wrong with the MRC. It stopped after a minute or two. WTF? The code has since cleared on its own and no more buzzing sound. HElp if anything sounds familiar.

The second character is actually a zero and not the letter "O", e.i. U0100.... so if you googled UO100 and got no hits try U0100... but I think your question has been answered.

The technical definition of U0100 is "Lost Comm. With ECM/PCM Module A"

Not sure what the lamen's definition is though :noidea:

Maybe when the battery went dead, and you tried to jump it with the dead pack, it tripped the code because of the intermittent 12v signal?

Thomas.

Hmmm. Sounds plausible indeed. I had the battery and alt. check since. Both good. The code cleared on it's own though. Thanks for all of the responses.