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Hello everyone. Thank you for accepting my question. I have a 2014 C7 Stingray that I replaced the battery in a few weeks back. All worked well for a week or so then one day I totally lost my AC then a day later I lost everything and cannot get the car to even crank over and now getting code U0100 with a code reader. I think my PCM needs reflashed. I am curious if I bought a tunner if I could reflash my PCM or is this a dealer issue. Thanks in advance.
That code is a generic communication issue. Low voltage seems to cause a lot of comm errors and other odd problems. Since you recently replaced the battery you should examine the installation and battery first.
Before you do anything rash - disconnect the negative battery cable for about 30 min and reconnect. Verify that both the positive and negative cables are pushed onto the battery posts, level to the battery, and tight. This will reset all computer / comm modules.
Also - make sure that the small black wire on the negative battery clamp is intact. If broken, this can lead to charging issues. See pic below:
If still no joy, have your new battery tested - you can get a bad one off the shelf.
Hello everyone. Thank you for accepting my question. I have a 2014 C7 Stingray that I replaced the battery in a few weeks back. All worked well for a week or so then one day I totally lost my AC then a day later I lost everything and cannot get the car to even crank over and now getting code U0100 with a code reader. I think my PCM needs reflashed. I am curious if I bought a tunner if I could reflash my PCM or is this a dealer issue. Thanks in advance.
--New member
It is unlikely the PCM needs to be reflashed. Just changing the battery should not affect the memory locations in the PCM that contain the programminng for the engine. U0100 is a communications code that just says something didn't communicate with something else. That can easily happen if you have a low system voltage. The first thing I would do is check to make sure the battery connections are clean and tight. Also check the other end of the battery ground cable where it is connected to the frame.
Well checked all the fuses again today. Checked battery connections. Pulled all the engine control relays and reinserted them. Pluged in the code reader and wallah no codes. Pushed the start button and my Stingray snaped to life for the first time in over a month. I don't know what I did to fix it but at least the car is running for now. Thank you for all tbe help. Happy Driver!!!
Make sure the cable battery connectors and battery posts are clean and free of all corrosion, as well. :
Also, I've seen people simply forget to adequately tighten one or the other of the connections. One other thing, it is NOT impossible to get a new battery that is bad. Not long ago I got a bad Optima that simply would not hold a charge, as a case-in-point. :
C7 Code U0100
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