Jump starting breaking auto stop/start?

[ChadM]

Has anyone had to jump start their gladiator? I had to jump started mine twice previously, and after both times the auto start stop failed. The dealership replaced the PCR? - The thing that monitors the aux battery voltage. I forgot what it was called but each time they load tested both main and aux batteries both times and determined it was the thing that monitors the aux battery voltage, and the batteries were healthy.
Trying to determine if this is a specific issue to me, or more widespread.
Note: both times was from having the doors off and my radio (aftermarket) kept running over a long 4 day weekend. I have since fixed that issue.

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[Steel24]

I believe I have the same problem when I use my winch. I have my winch wired to a solenoid and then wired to the battery. After each use my ESS stops working until I replace the pcr that’s mounted to the battery. Not sure how to avoid this from happening.

 

[ShadowsPapa]

I believe I have the same problem when I use my winch. I have my winch wired to a solenoid and then wired to the battery. After each use my ESS stops working until I replace the pcr that’s mounted to the battery. Not sure how to avoid this from happening.

The PCR isn't on the battery. The PCR is down by the aux battery.
The IBS is on the crank battery negative post and it's extremely rare to ever need to replace it. They just don't fail often. Reset it instead.

Jump starting according to directions doesn't ruin anything.
The PCR doesn't monitor anything. It's a relay that opens when you do a cold start, the PCM checks voltage, then the relay closes. It's not monitored.

 

[ChadM]

The PCR isn't on the battery. The PCR is down by the aux battery.
The IBS is on the crank battery negative post and it's extremely rare to ever need to replace it. They just don't fail often. Reset it instead.

Jump starting according to directions doesn't ruin anything.
The PCR doesn't monitor anything. It's a relay that opens when you do a cold start, the PCM checks voltage, then the relay closes. It's not monitored.

That is what is so confusing, it's not like jumping it is difficult, attach the jump box, start and go. I had to do that plenty in my old TJ leaving my lights on all the time. I guess I should try to drain my battery again and jump it and see if its 3 for 3

 

[ShadowsPapa]

That is what is so confusing, it's not like jumping it is difficult. I had to do that plenty in my old TJ leaving my lights on all the time. I guess I should try to drain my battery again and jump it and see if its 3 for 3

These are easy, and the Grand Cherokee even easier. They have posts on the right side of the engine bay to connect cables to. Hook up, and off you go.

Be careful how you drain your batteries - I've seen guys do it with screw drivers and pliers. Not on purpose of course. Man, the sparks fly and the tools get hot.

When my 2020 seemed to have issues after a couple of years. I separated the batteries at the ground cables, charged each individually with a newer AGM capable charger, reset the IBS and it helped.

I really had to laugh as the dealer thought my winch was draining the batteries. I guess they figured that big fat red SWITCH next to the battery was a prop, for looks only. I tried to tell them "switch off means NO power going anywhere".
Their fix? They moved the negative winch cable from the top of the IBS, where it belonged, to the ground stud on the right fender area. And guess where the cable from that ground stud goes to? The top of the IBS! They literally told me "we fixed the drain for you".
I wanted the throw up my arms and scream! It was still electrically exactly the same thing.
And they still ignored the big red switch that said OFF on it. (besides, since the winch ground cable bolts to the frame of the winch, and the winch bolts to the winch plate and the winch plate bolts to the truck frame and the truck frame is tied to the body via a ground cable - even without the ground cable, the winch is grounded via the frame, just not all that well.
I should offer to pay for some adult education on basic electricity at the local community college.

 

[Lunentucker]

Since the F42 fuse seems to the one that's linked to ESS, it may be worthwhile to pull that before jump starting. See if that makes any difference.

 

[ShadowsPapa]

That won't do anything. That only prevents the PCR from OPENING when you do a cold start. Pulling the fuse ensures the PCR doesn't operate and doesn't open. Otherwise the PCR is always closed except during a start cycle to check the aux battery voltage and during an ESS stop to isolate the batteries.
When jumping, the batteries are in parallel and pulling the fuse will keep them that way.
So it does nothing when jumping.

The PCR is a NC (Normally Closed) relay. It keeps the aux battery positive connected to the crank battery positive via high current fuse N3 and bus connection N2.
The electrical path connecting the two batteries - Aux positive to and through the NC PCR relay, to fuse N3, through N3 to the bus, out N2 to the crank battery positive.
The aux ground cable runs up to the crank battery negative.
**They are electrically tied in parallel at all times with 2 exceptions:

A. When you do a cold start, the PCM sends power to the PCR to open it for a brief moment, the PCM checks the voltage of the aux battery (via connection N1), and cuts power to the PCR allowing it to close again.
B. During an ESS stop event, the PCM sends signal to the PCR, causing it to open, breaking the connection to the crank battery, isolating it. The aux battery then only powers the system electronics and cabin electrics. It is otherwise not connected to the crank battery. This ensures the crank battery will indeed restart the engine because it's sitting isolated from other systems during an ESS stop event. In short, when the PCM stops the engine for an ESS event, the two batteries are no longer electrically connected. The crank battery is held in reserve to start the engine, the aux battery powers the PCM and other electronics.

** This is very important to note as if you pull the cable off the crank battery to do work on your truck, thinking it's safe as "the battery is now disconnected", only the crank battery is disconnected. The aux battery is STILL tied to ground via that ground cable and a cable from there to the right fender area near the crank battery. And of course the positive of the aux battery is still very much alive through the PCR back to the main power bus at N2 and N3.
When working with the electric system, you need to separate the aux battery ground cable from the crank battery ground cable and keep both from touching each other or other metal parts.

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