Voltage too high, Charge system fault
Thread Starter
Intermediate
Joined: Apr 2024
Posts: 29
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Voltage too high, Charge system fault
I just put in a new alternator after having some low voltage issues. When it starts up the voltage reads in the 14’s and so does the battery. Healthy right? My old alternator used to read 12.7 and battery 12.4. I used to get the charge system fault message every so often but consistently when in high rpms for a 5-10 seconds. Now my dash reads in the high 14’s and i get the message every 20 seconds or so. Whats the problem here?
Update: I originally had an undercharged battery when i let it sit for a couple weeks. I thought I had recharged it but the battery with the car off reads about 12V flat. Is this the problem? Is the alternator working overtime or something
Update: I originally had an undercharged battery when i let it sit for a couple weeks. I thought I had recharged it but the battery with the car off reads about 12V flat. Is this the problem? Is the alternator working overtime or something
Last edited by ls1mc5hane; Aug 18, 2025 at 09:44 PM.
Safety Car
Joined: Mar 2017
Posts: 3,771
Likes: 940
From: Orlando Florida
Sounds like at least one step away from the original alternator, with replacement alternators known to cause charge fault issues. Recommend a read of the alternator issues:
https://www.corvetteforum.com/forums...nd-issues.html
https://www.corvetteforum.com/forums...nd-issues.html
Tech Contributor
Joined: Jan 2007
Posts: 19,473
Likes: 1,171
From: Dyer, IN
Isn't C5Diag helping you in the other thread you started?
https://www.corvetteforum.com/forums...r-failing.html
https://www.corvetteforum.com/forums...r-failing.html
Thread Starter
Intermediate
Joined: Apr 2024
Posts: 29
Likes: 1
Isn't C5Diag helping you in the other thread you started?
https://www.corvetteforum.com/forums...r-failing.html
https://www.corvetteforum.com/forums...r-failing.html
Team Owner
Joined: Oct 1999
Posts: 31,977
Likes: 487
From: Guinness Its whats for B'fast JAWGA
CI 3-4-5-9 Veteran
I had an issue like this (high voltage and an error) Wires going to the starter were on the wrong post. If the starter came off for the headers I'd check them.
