Charging system

[Sardog]

I don't know if this has been posted before, if it has I am sorry. Currently have a 2020 Lariat with 20,000 miles. For the last 2 days I have been getting an intermittent "charging system requires service" warning light while the truck is driving. The battery light is illuminated for about 45 seconds and then it extinguishes. It happened this morning 5 times on my drive in to work at various engine speeds. The first time it happened yesterday I happened to be idling in my driveway so was able to get a multimeter on my battery. I am getting a solid 13.8V with the truck running and my battery stabilized at 12.4V with the engine off (Haven't been able to get a reading after it is off for a while yet). I am going to check all connections after I get off work, and pull codes to see if anything pops, but are there any other easy things I can check. I am not going to be able to take to the shop anytime soon so would like to check it out myself if able. The repeat pop up warning and tones are super annoying.

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[Porpoise Hork]

Sounds like a possible weak battery. Most OEM batteries give out after 2-3 years. Some last a lot longer where others fail much sooner.

 

[Sardog]

Sounds like a possible weak battery. Most OEM batteries give out after 2-3 years. Some last a lot longer where others fail much sooner.

That is what I thought at first as well, but have had no issues starting at all and I just checked voltage and it is right at 12.4V after being shut down for an hour. I did find one loose connection (not sure what it powers but it has a brown fuse labeled 225) other than. That everything looks solid.

 

[LoneRNGR]

I am getting a solid 13.8V with the truck running and my battery stabilized at 12.4V with the engine off

I don't get 13.8v with the truck running, at least not at the battery. The Body Control Module determines if the battery requires charging and sends voltage to the battery. There is a Battery Monitoring Sensor on the ground of the battery. If it gets unplugged (or is faulty), then the BCM would send 13.8 volts to the battery.

 

[Sardog]

I don't get 13.8v with the truck running, at least not at the battery. The Body Control Module determines if the battery requires charging and sends voltage to the battery. There is a Battery Monitoring Sensor on the ground of the battery. If it gets unplugged (or is faulty), then the BCM would send 13.8 volts to the battery.

sorry Typo, I just remeasured it is 13.08V not 13.8V.

 

[Grady]

That is what I thought at first as well, but have had no issues starting at all and I just checked voltage and it is right at 12.4V after being shut down for an hour. I did find one loose connection (not sure what it powers but it has a brown fuse labeled 225) other than. That everything looks solid.

Fully charge the battery, disconnect and let sit for 24 hours, then check voltage. This is the only way to determine battery health from voltage.

 

[LoneRNGR]

Fully charge the battery, disconnect and let sit for 24 hours, then check voltage. This is the only way to determine battery health from voltage.

Yes. This will also reset the BCM. Which might fix the issue.

 

[12Bravo20]

Newer vehicles with the Auto Start/Stop system can be very finicky at times when it comes to the batteries. And it doesn't really matter which brand either.

I had a 2016 Jeep Cherokee that the AS/S never worked right. I always got the same error messages: battery needs charged or service AS/S system. The battery and charging system always checked good. The only thing I did not test/replace was the intelligent battery sensor attached to the negative terminal. Which I am sure the IBS was the problem.

Have both the battery and IBS checked out.

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