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'Check Charging System' message...

s9669s

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A couple times at autocrosses, I've had a 'Check Charging System' message pop up in the cluster when restarting for my next run. Last year, it happened once, but I was never able to replicate it. (I also stopped shutting the car off between runs pretty shortly afterward, and no more issues.)

Today, it happened again. Then after shutting off and restarting to try to clear it, I got a MIL for a P260F (Evap system) fault code. The P260F did not happen last time.

I was able to clear the fault, and neither the fault nor the check charging system message returned, but I'd like to resolve it rather than hoping it does not come back. Has anyone else seen issues like this?

Of note, the car is a 2011 Mustang GT, and this has only happened at autocross events, and only when restarting the car (after shutting it off after a prior run). I also had an OBDLink MX connected both times when it happened (to log OBD data with the Track Addict app).
 
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s9669s

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No observed issues other than the message above. The battery was fresh when I bought the car last Spring, and seems solid.
 

s9669s

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I found another discussion here with similar symptoms where the issue was the PCM relay. Tried that as a quick and easy step, but no luck...

If I shut off the car between runs at an autocross, I still get the 'check charging system' message when I restart. This time, the P260F repeated as well.

It seems like this has to be heat-related. It only happens at autocross events, and only if I shut down the car between runs (without an extended idle prior to shutdown). If I let the engine idle between runs, no issue.

The battery is pretty recent, but I assume the alternator is original (2011 / 28k miles). Ideas/thoughts on likely root cause?
 

Anti

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This is a shot in the dark. I know on the 05 to 09 mustangs the alternator was poor at high RPM and would break. It wasn't until 2009 they released the denso brand alternators that could handle the RPM. I am pretty hard on my car even in normal street driving especially merging onto highways. My car started having the charge check charging system error also and after much testing I found it was my alternator giving up after so many high RPM instances. After I swapped to a denso version of the alternator it solved my problem. However through the process I learned a lot about the charging system in general. If your battery doesn't hold 12 volts of charge or higher while the car is off, your battery is already weak. If you use the same battery on and alternator or even a new alternator it could eventually ruin the alternator. the warranty for my new alternator stated this specifically. However it will not cause the check charging system error. Also with the vehicle running you should be getting a voltage that is higher than 12 volts. I can't remember exactly right now, but it's above 12.4 volts. I would have to Google what you're looking for, but I'm sure it's readily available. If your alternator is not putting out that power, it is suspect. however on my mustang it would put out that power level, but would occasionally stop doing that and thus the warning.

TL;DR

The check charge system warning is very likely your alternator. If you replace the alternator also make sure your battery is behaving in spec, because if it is not it can kill an alternator prematurely.
 

12coBoss

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I had this error pop up a couple years ago. No issues with power or anything just the error would pop up and mainly when running on track. Swapped the alternator and has been good since.
 

barstowpo

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I had this issue on my 350 after two days of spirited driving in Rosamond, CA. Mine turned out to be the alternator. Dealer still has my car. They had a hard time replicating the issue but it only took me a spin around the block to trigger the fault. Charging seemed erratic when the fault was showing but it seemed to reset itself if the rpm was kept low.
 

s9669s

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It sounds like an alternator swap is likely in my future...

Is the Boss 302 alternator kit the sweet spot in terms of cost/performance for an S197?

How difficult is the R&I on the S197 Coyote cars?
 

HF Bass

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Don't want to hijack the thread but I've also seen this issue quite often with my 14 GT, but I haven't seen any crazy drops in voltage while the car is running. It happened first time earlier last year but ended up being the battery, but it came back after my last outing before COVID. Do you guys think the stock voltage gauge is not accurate, and I may still have an alternator issue?
 

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