3.3TT Bad alternator?

[Dwayne]

Hi folks,

2019 GT AWD

Noticed my battery warning light was on yesterday, accompanied by a flashing auto start/stop light. Voltage on battery was 12.2v, voltage at battery when running was just over 13v, should be about 14.5v.

Anyone else experience this?

 

[5tinger]

Perhaps bad battery?

 

[Dwayne]

Perhaps bad battery?

Not sure. I load tested it and it was fine. I'm leaning towards alternator. Just have to remove my JB4 before visiting the dealer.

 

[Dwayne]

Not sure. I load tested it and it was fine. I'm leaning towards alternator. Just have to remove my JB4 before visiting the dealer.

And of course now everything is working fine again.

 

[CKeeler]

And of course now everything is working fine again.

Always happens like that

 

[MerlintheMad]

And of course now everything is working fine again.

Still could be alternator, because when they start to die it isn't always sudden; but also, usually doesn't take long; so, you could just "wait and see".

 

[oddball]

Note that the charging system on this car is far more complicated than a traditional car. Make sure there's zero corrosion on the battery terminals and everything is snug on that huge doohickey on the positive terminal (IIRC, they put the current shunt and voltage monitoring right on the positive terminal connector).
There's a ton of conditions where the computers would instruct the alternator to not charge, so definitely need full diagnostics to see what's going on. And note that the different computers can have different views of reality, so one computer could keep the alternator effectively disabled while another screams bloody murder about low voltage.

 

[JDM_Man]

Welcome to quarantine!!! If the cars are not driven for some time the batteries die out, sounds like you started the car up before it went completely dead and now after driving it's back to being charged.

Happened to me