Stop Vehicle Now - Updates Alternator ?

[sarguy1941]

No gas. I have JSCAN but don't leave module plugged in. Will hook it up Friday.

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[PuddleJumper]

ok so these trucks come with dual battery setup from the factory as a bandaid for thier ESS system (electronic start stop). The second battery is tucked under your primary battery and fuse box in the engine bay. Its basically a lawnmower/motorcycle battery. Its job is to just inflate the voltage available to keep essential power sensitive units from having a stroke when the vehicle starts and stops regularly. starting has a very heavy pull on a battery. basically if either battery starts to go the system will read lower than optimal voltage, cus two batteries to increase voltage also means a bad one is being a vampire to the other one. this is the case in which the very solution, has now become the problem. The right way to do this, would be like i did on my old Tundra which i made dual battery myself. you have a primary and secondary and smart charger/disconnect. this device keeps the secondary separate of your primary and its systems until it detects charging voltage, and hooks the two. so in a Jeep if implemented how i believe it should've been done. if the one of the batteries starts to go, it automatically disables ESS and separates the batteries. This way the alternator can focus on keeping everything running instead of getting overworked by a battery it cant charge. instead however Jeep went cheap, and you get OPs problem.

 

[WILDHOBO]

No gas. I have JSCAN but don't leave module plugged in. Will hook it up Friday.

Just curious. If it was, I thought maybe it was a def problem. But I don’t have the diesel, so I was throwing it out there without any more info than what I’ve read on the forum.

 

[GROGG]

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

This exact issue happened to me last weekend only I was driving. The dash lights went bazerk and the vehicle went into park. Good thing I was rolling at a slow pace.
My wife came out to boost me but that was no help so we say there for almost an hour charging the battery.
I got the Jeep home and put it on my intelligent charger for 24 hours. The battery showed 14.5 volts but the charge capacity was only 80% max.
Called my dealer and was told the batteries are crapped out. Warranty replaced them both and no issues after that.

 

[obrianmcc]

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

... This. You have to be careful when disconnecting and reconnecting the battery cables with both batteries active in the system. Ground out the positive and the array is toast. I don't get pulling the F42 fuse? ... just follow the Genesis Battery system for wiring/bypass for your year and that's all you'll need if deleting the AUX. The ESS is simply a function and has no relation to the AUX vs main issues.

 

[PuddleJumper]

basically yeah.

 

[sarguy1941]

OK> So update. Replaced both main and aux battery. Aux Battery showed 10.60 when removed. Main is 12.6.
Vehicle Off
New Battery Main - 13.12
Aux - 12.35

Both batteries have chargbed multiple times over night before I got home. Charger shows full on both.

I removed N1 and M3 and measured DC voltage on both cables and it matches the 12.35-49

Start vehicle and dash throws alarms and shows battery voltage 11.5

Battery Voltage with vehicle running 14.56

PCM Via JSCAN shows 11.37

I did continuity test on ZBar Fuse - N1 and N3 appear to be tied together. N2 and all other posts appear together. Voltage on all posts with vehicle off or on.

I'm at a loss. Checked F42 and fuse is good. How can it not show 12+ volts on PCM but show 14+ on battery when running.

 

[sarguy1941]

Well after more googling and looking around I went and removed the ZFuse and it appears N2 is blown. Now trying to find one anywhere local.

 

[WILDHOBO]

Well after more googling and looking around I went and removed the ZFuse and it appears N2 is blown. Now trying to find one anywhere local.

Good work. I hope you can find it easily.

 

[sarguy1941]

So $145.00 later new part installed. All codes cleared and jeep is running good. Just drove to dinner and when we first left got auto start not ready (about 20 miles into trip) but 45 minutes later it seemed to work pulling into O'Reilly's to drop off my old batteries and get core. Voltage is bouncing between 14.7 and 14.5 running. When it did stop at the light the voltage showed 12.6. I'm surprised the aux battery drops that far but I'll keep an eye on it.

 

[WILDHOBO]

So $145.00 later new part installed. All codes cleared and jeep is running good. Just drove to dinner and when we first left got auto start not ready (about 20 miles into trip) but 45 minutes later it seemed to work pulling into O'Reilly's to drop off my old batteries and get core. Voltage is bouncing between 14.7 and 14.5 running. When it did stop at the light the voltage showed 12.6. I'm surprised the aux battery drops that far but I'll keep an eye on it.

Is that the total cost of two batteries, and the fuse? It sounds like that fuse might be something to put in the glove box as a road spare. What kind is it?

 

[sarguy1941]

No batteries were $249 for main and Aux was $114 plus cores. The Z Bar or what ever they call it fuse was $145 with tax. Typical dealer. Could have got for $75 online but needed to fix truck. I may grab another to leave in the shop but my guess is when they tried to jump it they hosed it up.

 

[WILDHOBO]

No batteries were $249 for main and Aux was $114 plus cores. The Z Bar or what ever they call it fuse was $145 with tax. Typical dealer. Could have got for $75 online but needed to fix truck. I may grab another to leave in the shop but my guess is when they tried to jump it they hosed it up.

That sounds likely. Is it a mopar part number then? Do you mind sharing if you have it?

 

[sarguy1941]

Yes Mopar Part. I can share when we get home old one is on table.

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