Last week we wrote about Silverado and Sierra owners reporting that their brand new auto stop function was working sporadically or even not at all. Included in those reports was us and our 2019 Silverado LTZ. When we took our truck to the dealer, even our amazing service tech couldn’t immediately figure it out.

During the same time frame that our auto stop stopped working, we had also noticed our Silverado started to shift slightly softer and the dynamic fuel management also seemed to work far less aggressive as well. Again, same with the auto stop, we figured the cold weather was to blame.

Well, turns out it was, but not in the way we would have ever thought. Our battery was going bad. And when your battery starts to go bad in new gen 2019+ Silverado or Sierra, apparently things stop working. Typically, batteries do not go bad in a vehicle under 5 years old, so this one was a surprise to us.

Here’s how it was explained: When our Silverado’s body control module saw that the battery was under 75% charge it disabled the auto stop functionality. That “low battery” flag also had an effect on the DFM and engine control systems we assume, because after our battery was replaced under warranty, our Silverado drove with a crispness we had not felt in months. So, we can only deduce that various and wide ranging vehicle functions are changed, modified, or disabled, when the battery drops below 75% charge.

Let this be a lesson to every 2019+ Silverado and Sierra owner out there. Check your battery! Live in a cold climate? Buy a battery tender. Even then, if the battery starts to go, get it fixed quick. It seems bad and/or weird things will start to happen in your vehicle with a failing battery. Including potentially even disabling your brake system.

But fear not, your factory battery should be covered under the bumper to bumper warranty period of three years or 36k miles, if you catch it in time.