P00FD after battery swap

[tastetickles]

Long story short, ESS warning came on. I removed both batteries and the AUX is one cell dead at 10.5v, I replaced both batteries and the ESS warning remains. I had reset the IBS after battery installation but I had not load test both batteries because i dont have a load tester. After several drive cycles, the warning remains lit so i hook up jscan and got the code P00FD which implies the new AUX battery is falling below voltage threshold during cranking. Cleared the code and start the car again and the code came back.

After reading a lot off JT and JL forum, noone mentioned whether the warning light would go off or not upon battery swap. However I stumbled on the Pacifica forum that one owner confirmed upon battery swap and if both batteries are good, the ESS warning light should turn off but the ESS will not activate until 5 drive cycles with 4 hours gap in between. Since the warning light on my car never turn off right after battery swap, am i right to assume the new aux battery is indeed bad when i first got it?

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[PuddleJumper]

possibly or you just need to give it a good charge. Those batteries could have been sitting on a shelf for too long and need a kick. leave it on a tender or drive it for an hour or so to actually charge everything up. Did u voltage test the new batteries before install?

 

[Lunentucker]

View attachment ELECTRICAL Battery (Service Information).pdf

 

[tastetickles]

possibly or you just need to give it a good charge. Those batteries could have been sitting on a shelf for too long and need a kick. leave it on a tender or drive it for an hour or so to actually charge everything up. Did u voltage test the new batteries before install?

Ya voltage was good before installation. I have driven for quite a bit now and the warning light still hasn’t go away. However I have not have done the required number of hours between drive cycles.

 

[PuddleJumper]

Ya voltage was good before installation. I have driven for quite a bit now and the warning light still hasn’t go away. However I have not have done the required number of hours between drive cycles.

Have you cleared the light to see if that ship it off?

 

[sharpsicle]

possibly or you just need to give it a good charge. Those batteries could have been sitting on a shelf for too long and need a kick. leave it on a tender or drive it for an hour or so to actually charge everything up. Did u voltage test the new batteries before install?

This.

If it were me, I'd disconnect them and charge each one individually (no need to remove, just isolate), then hook them back up. It's a simple thing that you can do to eliminate a possibility. Don't rely on driving around to charge up new batteries.

 

[Lunentucker]

Here's the charger / tester that Jeep recommends.
What? You don't already have one?

https://www.toolsource.com/battery-...king-diagnostic-battery-charger-p-141669.html

 

[tastetickles]

Have you cleared the light to see if that ship it off?

Yes, the light comes back every time the car is started with the 2 batteries (not isolated) with surface charge voltage 12.8 volts

This.

If it were me, I'd disconnect them and charge each one individually (no need to remove, just isolate), then hook them back up. It's a simple thing that you can do to eliminate a possibility. Don't rely on driving around to charge up new batteries.

I guess that’s the only thing to try now and buying a load tester.

Here's the charger / tester that Jeep recommends.
What? You don't already have one?

https://www.toolsource.com/battery-...king-diagnostic-battery-charger-p-141669.html

LOL

 

[tastetickles]

Problem solved. Aux battery lost a cell and replaced with a new one. So the warning light turns off but ESS will be disabled until the IBS works out the battery SOC is correct according to the Pacifica forum.

 

[Hootbro]

Problem solved. Aux battery lost a cell and replaced with a new one. So the warning light turns off but ESS will be disabled until the IBS works out the battery SOC is correct according to the Pacifica forum.

So the replacement AUX battery also lost a cell and you are on your third AUX battery currently?

 

[tastetickles]

So the replacement AUX battery also lost a cell and you are on your third AUX battery currently?

Yup.

 

[Hootbro]

Yup.

That is some weird odds.

Might want to entertain a full aux battery delete once out of warranty.

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