Stop Vehicle Now - Updates Alternator ?

[sarguy1941]

So wife called today. She got this on dash and now vehicle wont start. In middle of intersection. I know the batteries are not great (2020JT) and had planned to change them this weekend. Anyone know how to get the vehicle home. She can jump start it but it just pops up and shuts off again. We noticed it acouple weeks ago car starter wouldn't start vehicle and it barely started. Used jump pack to start and had been putting charger on it at night. Just drove it Friday with no issues. Voltage showed 14.1

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[bleda2002]

So wife called today. She got this on dash and now vehicle wont start. In middle of intersection. I know the batteries are not great (2020JT) and had planned to change them this weekend. Anyone know how to get the vehicle home. She can jump start it but it just pops up and shuts off again. We noticed it acouple weeks ago car starter wouldn't start vehicle and it barely started. Used jump pack to start and had been putting charger on it at night. Just drove it Friday with no issues. Voltage showed 14.1

14.1 is the alternator charging, not the actual batteries. Bypass the aux small battery by pulling the ground and fuse, then change the 12v and see if that gets you going.

 

[sarguy1941]

Well had them remove F42 and remove the aux battery. Everything shut off in vehicle. I had them reconnect just the main battery cable and when they jump it it will start and same error then shut off. So called a flatbed. Can't shift it in N either so had her pop transfer case in N and put on EBrake.

 

[Hootbro]

I suspect something with the high amp fuse array on the side of the PDC fuse box if new batteries do not fix it.

 

[Rocksalt]

test main battery voltage with a multimeter .. if less than 12.3 volts then maybe replace the main battery

 

[sarguy1941]

I won't be home until Friday. Tow truck got it in driveway. I know the batteries need replaced. Just shocked that it would just quit in the middle of an intersection.

 

[Camaroboi13]

In a perfect world, you can start a vehicle and remove the battery completely and it shouldn’t turn off. The alternator runs the electrical system while the vehicle is running, no battery required. First thing I would look at is alternator, then batteries, then wiring harness.

 

[sarguy1941]

I agree. Done that in the past multiple times. Each time vehicle would start with jumper cables attached it would throw the code on dash then shut off. Very odd. I'll check alternator also Friday. It showed 14.2 all weekend and 12.1 when vehicle was off. Today she said it showed 11.9 until they hooked up jump pack then 12.3. still wouldn't start so they jumped with other vehicle and it showed 13 volts. She started truck, message came on dash and truck shit off.

 

[dmwphoto]

I know this is a typo, but perfectly describes the situation.

and truck shit off.

 

[GeneralMaximus]

Go up to the search function and type in “F42” and then read to your hearts content. There must be hundreds of posts about the Aux Battery here

 

[Escape.idiocracy]

test main battery voltage with a multimeter .. if less than 12.3 volts then maybe replace the main battery

So, I was just out playing with Jscan looking for IBS %….
anyways, my jeeps batteries are a couple months old and regularly show 12.2-12.4v resting voltage….
Jscan shows the battery life at almost 87%.

I am saying the table below is gospel… but it seems to be pretty close

OP- Jscan is fairly simple to navigate for the basics of reading codes and what not. This won’t help you at all now. But might be worth downloading the app- same for your wife and keeping this in the center console:
https://a.co/d/fCBMkU4

 

[WILDHOBO]

I don’t think anyone asked this, but is it a diesel?

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