Check charging system - but different this time

So recently, I did a fair bit of electrical upgrades and changes to my 2019 TRD Pro. I installed a new AGM starter battery, as well as a larger AGM house battery. Both are the x2 line from batteries plus, and they are slightly different capacities. The two can be isolated or combined using the Blue Sea automatic charge relay I also installed. Currently, the house battery only powers my 2500w pure sine inverter which is behind the back drivers side seat. That inverter must be manually turned on; it does not run continuously, meaning there really is little to no draw on my house battery.

Second phase of these upgrades was to get my truck tuned by a local reputable tuner, who also bumped my voltage on my request, since the AGM batteries appreciate a higher voltage from my research.

All of this work was completed over a week ago, and since then I have put few hundred miles on my truck with zero issues, and everything working great. This afternoon, I drove from Austin, TX to Galveston, just south of Houston. Trip total of just over 200 miles. This evening, after running some local errands, I got back in my truck, started it as usual, and was presented with the Check Charging Sytem message.

Great, something went wrong with my system, right? Not that I can tell! Everything is fully operational, all voltages look good. I even went so far as to run the truck down to AutoZone to have the electrical system tested. I completely isolated the two batteries, and had their guy test the starter battery and the alternator. Both checked out just fine.

I checked for any OBDII codes, but there were none stored.

Any idea what could possibly cause this, or where I should start looking?

The issue, with truck running:


I have my house and starter wires on the wrong pins here, so they're reversed. The top 'main' battery is actually my house battery. In this picture the batteries are isolated from each other, hence the different voltages.


Thoughts? What am I missing?

I've made sure the batteries are isolated, and then disconnected the negative connection on the starter battery. I'm going to let it sit until morning and see what happens.

 

What happens when you clear the warning? What happens when you restart? Does the warning come back or was this one time?

 

If I clear the warning, it keeps the red exclamation point on the info tab of the display, and then the big red warning comes back within a minute or two.

Unfortunately restarting the truck has no effect, the warning shows back up immediately. It has stayed on for several start cycles now.

 

I would put a techstream on it and get some data.

 

He tuned you with an ecm tune right?

maybe @caribe makaira has some code setting criteria for the check charging sys “code”

 

Yes, ECM tune, correct.

 

Something in your system is confused. That comes on in these trucks when it’s running off battery power alone. Happens to a friend when he’s sitting in his truck for lunch listening to the radio and then goes away when he starts it. You probably already know that part. You have altered a complicated electrical system designed to function a certain way the voltage it puts out and the computer that controls it. Hopefully someone has an easy fix for you but you are probably going to need a skilled technician with some expensive diagnostic equipment to find the cause of this.

 

I just got done skimming the Blue Sea FAQs. I think maybe you should read them and see if it operates like you think it does.
One thing I noticed; it isolates or combines using certain voltage thresholds, that you've modified with a tune.

 

you should use a scan tool to check the voltage while it is running. Try to see what the ecm thinks the charging circuit is doing. But my money is on the voltage bump from the tune. You really haven't changed the charging circuit by adding batteries, it should still make the same volts. However that tune certainly does, when something is broke go find the last guy who put his mits on it.

 

AGM batteries should be charged at a higher voltage else they will not fully charge thus limiting their lifespan. Its common for 3rd gen tunes to be customized to bump up the alternator output voltage to 14.4ish to accommodate the AGMs

 

Yeah, my truck is happily running the tune with AGM voltage adjustment.

 

You could be over or under charging one or both of your batteries. 2 agm batteries, a tune, sounds like a lot going on.

 

Just got back into town and wanted to jump into this thread. I'm the tuner in this story, and since the issues cropped up so quickly after the tune, I'm assuming the new alternator settings I did not jiving with the battery hardware is the culprit here. My first course of action will be to get @BirfMark back here to retune, but with the stock alternator settings. Once the new settings are removed from the equation, we can clear codes and see if the issue persists. My assumption is that some of the extensive hardware on the truck is expecting stock voltage from the alternator, and getting more than it expects. I'm thinking the codes are probably from too much voltage, not too little. If the stock alternator settings solve the issue, I can always increase the voltage getting pushed to the batteries by a smaller %.

Edit: I do also have techstream, and can run through the steps that @caribe makaira provided if the alternator settings reset doesn't immediately fix.

 

My cousin's '17 got this message a couple months ago and he said the dealer replaced the crank sensor. Not sure how they would be connected, but there was nothing wrong with his charging system.