Code u0100?

2012 BUICK LA CROSSE
120,000 MILES • AUTOMATIC
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DOUGPARKS567
  • MEMBER
  • 60 POSTS
Hello, I have the car listed above that will not start sometimes and I'm getting a code u0100 ECM lost communication. I wanted to know what the issue could be. I also broke my fob key out of the fob but can still use it to turn the car on and start it when it decides to start, could this be the issue?
May 24, 2023 at 4:46 PM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,176 POSTS
It sounds like the PCM went out or you have some fuses out. you can get a preprogrammed unit by searching Google or Ebay.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuses are okay, I would replace the PCM.

Here is a guide to help and the instructions for your car in the images below:

https://www.2carpros.com/articles/how-to-replace-a-vehicles-main-engine-computer-pcm-ecm-ecu

The OBD-II trouble code U0100 stands for "Lost Communication with ECM/PCM."

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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May 25, 2023 at 11:25 AM
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