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Hi guys, new here. Im working on my moms 07 Aveo, its throwing a U0100 code. Ive tried searching for threads on here but havent read anything on what has actually fixed these issues. Ive already replaced the ecm and tcm. Anyone else with this issue? If so what resolved it?
It might be helpful if you posted the history of this vehicle. What else (if anything) is happening, in addition to the U0100? Was any recent work done before the code started? Was it ever hit, or had any water damage? Have you had the battery and alt tested, and checked all of their connectors and wires (grounds in particular)? You should reinstall the original factory parts before you do anything else, to eliminate the possibility of something related to the new computers sending you in the wrong direction.
Its like the trans just loses all input. If I clear the codes it will tun fine till 35 mph the it just drops out. After that I get no movement from the car until codes are cleared again.
By "drop out" do you mean engine (and everything electrical) shuts down, or is it just the tranny quitting and the engine revs up and stays running? I can't imagine clearing the codes with an OBD reader would "fix" the problem, so I'm guessing you're getting rid of the codes by disconnecting the battery?
No, I mean drop out as if it goes into neutral. I guess what I was asking if anyone else had the U0100 code causing the trans to stop working? I've seen a few posts about U0100, but no one has posted a resolution to the problem. I work in a prototype engine lab and have 15 years experience working in shops and I have used forums before for help on unfamiliar issues. So, if anyone has had this code and resolved it, what did you do to fix it? I've replaced the controllers for the engine and trans, my next step is wiring harness. Batt and alternator are good, I've tested those. I've exhausted any problem I can think of besides the harness itself. I'm thinking maybe the CAN connections between the ECU and TCU are broken some where.
Spending time on the forums, you know that the percentage of problems with a posted resolution is REALLY small. So much so that I'm generally surprised when someone actually does follow up with an outcome on a thread they started. Sometimes I think this one is worse than most, but IDK because I cruise a bunch of other lousy ones as well. So I'd be fairly surprised if anyone gave a resolution to something like a U0100, which certainly isn't typically going to be a quick and easy fix.
I'm wondering if the tranny is having some problem of its own, sending it into limp, and then for whatever reason can't send that info back to the ECU. Nothing but speculation there, but just curious if you tried driving it in 3 and L to see what happens with those.
Have you tried probing wires at the TCM connector? It looks like CAN high is purple at pin 17, and low is yellow at pin 7. If the TCM always shuts down around 35, maybe you could put it up on stands, put it into D, and monitor what those wires (and others) do as the speed goes up. Good luck in any case!
??Quote:
Originally Posted by mikebridson
http://www.aveoforum.com/forum/f108/...ping-up-16771/
Posted my nightmares with U0100 and the solution....
Mike,
Did you clean C101 under the coolant tank??
Gosh it pains me that you did not find my post on this, it sends so many Aveos to the crusher and it's one tiny connector to clean. You should find all the dirt in my post, it's something I try to forget LOL - PS: Both our cars run fantastic in the past 5+ months, so I know C101 is worth looking at if missed thusfar.
Hi 06T200 could you post a link to that fix article.
Thank you.
levidoug/Doug
Doug, I can't post PDF docs here unfortunately, so refer to my post #7 (the link in it) above for my history on U0100. If anyone needs the TIS bulletins or the wiring diagrams maybe PM me your email address and I can email them. Keep in mind they just say 'clean all connections', the challenge is finding them all. There are three spots you need to clean/check, (for U0100) from my old memory I recall G103 under the starter (the grounds), and C101 which is hidden under the coolant tank, the other is under the dash near the TCM if I recall that needed to be cleaned as well, but C101 (which is the CAN bus, and the backup lamp circuit) was the one firing the U0100 code as we have never seen it since the day I cleaned THAT connector. It is about a 30 minute job, but don't expect any dealers or shops to know anything about C101 as they all missed it. Hope that helps.
Attachment 9479
My attempt to post the wiring diagram showing C101 and why it should be cleaned when chasing U0100, it carries the CANBUS traffic between ECM/TCM, along with the ground (to G103) and the backup light runs through it as well. Hope this works.
G103 You will find this on the bottom starter bolt under the engine. Make sure it's tight AND clean, it grounds the entire PCM chain of modules.
Attachment 9480
Yes it does. I will work at those between now and Sunday.
Thanks for the help.
levidoug/Doug