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Car didn't start, was clicking but after a while it started, what could it be?


Topic starter

Hey Scotty I have a 2008 Chevy Aveo5 Automatic with around 158,000KM, when I came to start the car it did not start and kept clicking. After waiting a while it started, why is that? I scanned it and the battery was good but there was a code "U0100-04" what does the code mean? Thanks for your help.

5 Answers

Of course everything is insane computer run but often the simple thing is either you have a loose battery terminal or the battery starting to go out because that's very common you can lose communication to the computer bus line when you don't have enough power and a loose battery terminal can do all that

Thanks Scotty!


This is, indeed, a communications error code. The ECM is having trouble reading bus data. Now, realize that that is a very vague code and could still be any number of things. I would:

1. Check connections to make sure they are tight and not corroded

2. Check the battery and make sure there are no issues there


If both check out, I would say you have a wiring short somewhere in the vehicle and in order to find it you would have to test sections of wiring which is more of a pain than it is worth for you to do and not worth the cost to pay someone to do. You may just live with it honestly.

I will check the connections, hopefully there is no wiring short. Thanks for your help.


Sounds like either the battery or the starter.


Try looking up the code online or have a part store hook up their scan tool to read it. Did you check alternator? To me it could be starter going bad based off what you said. 

@mod_man I know with your experience you might be able to add to or correct me if I’m wrong.

Not a bad guess or bad advice. I'm still at my shop, so I cheated....looked up the code on the computer. Lol.

I will check the alternator and starter. Thanks for your help.


The ECM has lost communication with the engine because of poor electrical connection, wiring harness shorts or a bad ECM.  Check all you plug in connections for corrosion  or disconnect.

Also, have the battery load tested, you could have a shorted cell.

I did load test the battery and it was good. I will check the electrical connection. Thanks.