I have a 2015 EX, 4 cylinder, 2.4l, and I have been getting the “check charging system” error. It comes on when I start the car on occasion, seemingly if it’s only after I make a quick trip into a store or something along those lines. It won’t do it if it sits for while, like if I’m at home or at work. The red battery light comes on with it too. It would only come up very briefly, and then go away. It never comes on while driving. It also seems to come on when the fan/compressor kicks in, but only briefly. Everything electrical seems to be working fine. The battery is at about 12.25v and alternator at about 14.4v. Any ideas?

 

Normal charge is 12.6V, so you are slightly low. The battery voltage really depends on how you are measuring it. For static voltage, turn on the headlights with the engine off. Then measure the voltage. This will remove the surface charge and give a better measurement. If the voltage drops to 10.4V very quickly, you have a dead battery cell (batteries have six individual 2.1V cells). If the battery voltage drops about 0.1V every few seconds, the battery is likely ok.

For the engine running, turn on as much electrical stuff as possible to load the system, then measure the battery (alternator) output.

You can also try the same measurements from the + battery post to where the negative battery cable connects to the fuse box, the body frame, etc to see if you have a connection or battery cable issue.