Hi, I've been having this weird issue with my car where anytime I either
a. accelerate at a normal pace, or
b. try to go over 60 mph,
the voltage gauge maxes. If I don't immediately take my foot off the gas I get a "check charging system" message and the entire battery shuts off while I'm driving, so I can still drive but theres no gauges, radio, a/c, and I can't even roll my windows up or down. Took it to autozone to have alternator and battery tested, alternator came back fine but they said I needed a new battery. Got a new one and it's still doing it. I'm thinking maybe it could be something to do with the wiring? Any help would be appreciated. Thanks!
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Hello,
The powertrain control module houses the voltage regulator. When functioning normally it will prevent the alternator from charging the battery above the specified range (about 15-16 volts). When the voltage regulator fails, you get this issue.
If that is the issue (which it likely is) you could either replace the powertrain control module or you could add a voltage regulator between the powertrain control module and the alternator.
To test, you will want to verify the voltage at the battery is the same voltage as you are seeing on the gauge.
If there is a battery sensor, it might be the culprit as well and should be tested.
