Service Battery Charging System - 2007 Tahoe

[FAUST]

this error message just started to show up in the last week.

New battery - less than a year old.

Alternator has been tested just the same, for some reason I don’t trust the test.

The battery meter is strong at just past 14 and the error does not change/impact the meter.

Checked connections to battery and alternator - clean.

The indicator and message are on no more than a few minutes then turns off.

Not sure if it’s related but all the lighting on the truck flickers with the idle - headlights, dome lamps, backlights on gauges and instrument panel - can’t figure this one out.

I always assume electrical is tricky and time consuming to diagnose, but willing to try anything before spending a bunch of money to have a shop diagnose and fix.

Any ideas on next steps?

Thank you all who help!

 

[gmgirl77]

this error message just started to show up in the last week.

New battery - less than a year old.

Alternator has been tested just the same, for some reason I don’t trust the test.

The battery meter is strong at just past 14 and the error does not change/impact the meter.

Checked connections to battery and alternator - clean.

The indicator and message are on no more than a few minutes then turns off.

Not sure if it’s related but all the lighting on the truck flickers with the idle - headlights, dome lamps, backlights on gauges and instrument panel - can’t figure this one out.

I always assume electrical is tricky and time consuming to diagnose, but willing to try anything before spending a bunch of money to have a shop diagnose and fix.

Any ideas on next steps?

Thank you all who help!

I dont know if its much help, but my 2016 Yukon had the same message on Friday. I was 40 miles from home and I barely made it to the driveway. It was the alternator, that I have replaced in the last 3 months. I have also replaced my battery in the last 3 months. "Service Battery charging system" came up first and then "battery saver active" came on. Same deal, lights flickered but then I lost all power. I have an electrical drain somewhere but I dont know where.

 

[FAUST]

Ah man that’s rough. Mine has no issues with power other than the flickering. I hope there is more responses to this.

I’m thinking it’s a connection somewhere, there is a ground connection ima clean and see if it helps.

 

[swathdiver]

Ah man that’s rough. Mine has no issues with power other than the flickering. I hope there is more responses to this.

I’m thinking it’s a connection somewhere, there is a ground connection ima clean and see if it helps.

In the morning, before you start the truck, put a voltmeter on the battery and note its voltage. Compare that with the ambient temperature at the time and looking at a battery chart online you can determine its state of charge.

If you have a bi-directional scan tool like the Tech-2, you can see this inside the BCM under Charging Info and also test the output of the alternator and of course, pull up the internal codes related to this.



A battery with a state of charge of 64% or less after sitting 24 hrs is considered discharged and in need of replacement.

 

[FAUST]

In the morning, before you start the truck, put a voltmeter on the battery and note its voltage. Compare that with the ambient temperature at the time and looking at a battery chart online you can determine its state of charge.

If you have a bi-directional scan tool like the Tech-2, you can see this inside the BCM under Charging Info and also test the output of the alternator and of course, pull up the internal codes related to this.

View attachment 409971

A battery with a state of charge of 64% or less after sitting 24 hrs is considered discharged and in need of replacement.

To be clear about the chart - let’s say it’s 56 in the morning - if the meter reads 12.224, it’s considered discharged?

Sorry for my ignorance - I have not seen a chart like this and want to be sure I understand how to read it.

 

[FAUST]

53 degrees -12.12

 

[FAUST]

The battery is less than a year old - would this be an indication the generator isn’t operating properly?

 

[Geotrash]

this error message just started to show up in the last week.

New battery - less than a year old.

Alternator has been tested just the same, for some reason I don’t trust the test.

The battery meter is strong at just past 14 and the error does not change/impact the meter.

Checked connections to battery and alternator - clean.

The indicator and message are on no more than a few minutes then turns off.

Not sure if it’s related but all the lighting on the truck flickers with the idle - headlights, dome lamps, backlights on gauges and instrument panel - can’t figure this one out.

I always assume electrical is tricky and time consuming to diagnose, but willing to try anything before spending a bunch of money to have a shop diagnose and fix.

Any ideas on next steps?

Thank you all who help!

FWIW, I consider alternators to be a maintenance item. I'm running this one in both of our Yukon XL's and they've been flawless for about 40K on one and 25K on the other. And they seem to handle AGM batteries just fine. For $120 it's a no brainer to swap it out every 100K or so.

https://a.co/d/ixW0rnY

 

[FAUST]

53 degrees -12.12

Checked alternator also - not anywhere close to 14 - it’s below 5 - I’m using DC volts to check, is that right?

 

[FAUST]

Checked alternator also - not anywhere close to 14 - it’s below 5 - I’m using DC volts to check, is that right?

I’m a noob - the alternator is working - reading at 14.39. I wasn’t reading it properly - setting was wrong.

So, battery seems on low side of charge based on the chart, but alternator is working…not sure where to go from here other than check all connections and wires.