[JaredG_F30]

Hi Fellas,

So I've been battling some battery and potential alternator issues. About 2 months ago I noticed my car wouldn't start in the morning. The car is a 2014 and had the original battery so I did a battery test and found the battery to be at its end of life and replaced it. I registered the new battery with ISTA+ and all was good but a few days later I get a "Charging System Malfunction" error on iDrive and subsequently the following morning my car wouldn't start and I had to jump it. Anyway, long story short, I'm suspecting my alternator is on it's way out. Is there a way to run an alternator check with ISTA+?

[atzebmw]

Do you have a voltage meter?
Then you only have to measure the voltage at the battery or at the charging point while the engine is running.
If the voltage is around 13.8V-14.4V, the generator should be fine.

[Billfitz]

The easiest way to test alternator function is to plug a voltage tester into a power socket, start the car, then disconnect the negative battery terminal. If the car dies right off then the alternator isn't working at all. If the car still runs but the voltage reads lower than 13v something is not working to spec, although it could be another component that's sucking up all the juice, which is another reason why the battery isn't charging.

[JaredG_F30]

Thanks guys. I also noticed there are a couple of diagnostic channels I can log through bootmod3 including "Battery Voltage from the AD converter detected value" and "Battery Voltage". I wonder if these can provide some insight. I do have a meth injection system hooked up so I may need to double-check the wiring to make sure I don't have an issue where it's pulling power from the battery when the car is off. Lastly, I've pulled some error codes ad get a "Faulty Falling Asleep" error which is interesting. I'll do some more digging before pulling the trigger on an alternator.

[Billfitz]

If it's that easy to check the battery voltage do so when you put the car to bed for the night and do it again when you wake it up in the morning, before starting the car. If it drops more than a half volt overnight something's not shutting down.

[JaredG_F30]

Thank you sir that is a good test to run.

Originally Posted by Billfitz

If it's that easy to check the battery voltage do so when you put the car to bed for the night and do it again when you wake it up in the morning, before starting the car. If it drops more than a half volt overnight something's not shutting down.

[JaredG_F30]

So I think I have this resolved. Yesterday I went to start my car and it would not start at all, even with a battery jumper. I tried both my battery pack and Stanley battery charger which has a jump mode. I figured I must have a loose ground cable since I was getting a DTC 804095 Driver KL50L: Current Overload. I started inspecting all my cable connections and found a slightly loose power cable that runs from the starter to the cable that connects the positive jump point that's found under the cover at the fuse box on the passenger side. I tightened that up and the car started right up. Being that the loose cable is in series with the cable from the alternator, I'm hoping this was the root cause of the intermediate charging malfunction.