Auto Start/Stop issue continues even after aux battery replacement.

[Mojofallen]

I've continued to have the same issue on my 2021 JLR with the auto start/stop unavailable message sporadically appearing. My JLR has 6k miles, I've taken it to the dealership for diagnostics multiple times, but they never found anything. Supposedly, my aux battery is working fine but they can't give an explanation as to why I keep getting the message. The dealership was very cooperative and conducted an Indepth testing of the aux battery. On the 10th attempt, they confirmed the aux battery failed. Great, they replaced the aux battery, and I was good to go. I disabled the auto start/stop feature on my drive home from the dealership, and the same message appeared again. I informed the dealership of the incident, and I will be returning the JLR to the dealership for a 3rd time within a week. My 36-month warranty ends in two weeks, I am concerned because the technicians are clueless as to the root cause.

I'm trying to throw a hail Mary before my warranty expires. Does any know if the dealership will resolve this problem even after the warranty expires if they don't fix it by then?

I could use Roger Staubach and Drew Pearson right about now.

Alfonso

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[Yawnie'sPapa]

I've continued to have the same issue on my 2021 JLR with the auto start/stop unavailable message sporadically appearing. My JLR has 6k miles, I've taken it to the dealership for diagnostics multiple times, but they never found anything. Supposedly, my aux battery is working fine but they can't give an explanation as to why I keep getting the message. The dealership was very cooperative and conducted an Indepth testing of the aux battery. On the 10th attempt, they confirmed the aux battery failed. Great, they replaced the aux battery, and I was good to go. I disabled the auto start/stop feature on my drive home from the dealership, and the same message appeared again. I informed the dealership of the incident, and I will be returning the JLR to the dealership for a 3rd time within a week. My 36-month warranty ends in two weeks, I am concerned because the technicians are clueless as to the root cause.

I'm trying to throw a hail Mary before my warranty expires. Does any know if the dealership will resolve this problem even after the warranty expires if they don't fix it by then?

I could use Roger Staubach and Drew Pearson right about now.

Alfonso

There's a list of things at least 24 items long that must be just right before auto stop/start will function. That ranges from cat temps across the map. If you scroll down on the cluster display it shows the consumer controlled things like steering wheel angle, engine temperature, cabin temperature and battery - in that case is says not available, battery charging.
But for the other stuff, it can even be a MISFIRE event.
My new 2022 JT with about 80 miles on it tossed me that message and it was due to an obscure misfire event - happened only on a hot restart and reset itself after a couple shutdowns and startup cycles - until it happened again then it would disable the auto stop/start and NOT always set a MIL (Malfunction Indicator Light).
If anything is sensed to be wrong with the engine, transmission or certain censors, it will disable auto stop/start.
Since my misfires didn't always set the light, I had to read stored codes and coordinate the events when ESS didn't function.
It's a good indicator that something is wrong with the Jeep, IMO. If it's not working, something is wrong somewhere and it takes some digging to find it if there aren't any stored codes. Could be the temp sensors for the cats never get up to temperature, that would do it, ABS issues, and so on.
It's not always about batteries. (and it can be a main battery issue as well)
My testing has shown that during an auto stop/start event, even though disconnected from each other by the PCR being opened, they both drop voltage at a similar rate while it's stopped. If the aux battery was at 12.3, the main battery wasn't far behind.
I'm going to wire my own Jeep up again to do more tracking and recording of what goes on during such events, but I'm seeing that they have done an incredible job of splitting the load across both batteries during such a stop.

 

[Under-Pressure]

It sounds like your Jeep might qualify for the Lemon Law at this point? You have certainly given them enough attempts to repair.

Maybe @JeepCares can help?

 

[58Willys]

There's a list of things at least 24 items long that must be just right before auto stop/start will function. That ranges from cat temps across the map. If you scroll down on the cluster display it shows the consumer controlled things like steering wheel angle, engine temperature, cabin temperature and battery - in that case is says not available, battery charging.
But for the other stuff, it can even be a MISFIRE event.
My new 2022 JT with about 80 miles on it tossed me that message and it was due to an obscure misfire event - happened only on a hot restart and reset itself after a couple shutdowns and startup cycles - until it happened again then it would disable the auto stop/start and NOT always set a MIL (Malfunction Indicator Light).
If anything is sensed to be wrong with the engine, transmission or certain censors, it will disable auto stop/start.
Since my misfires didn't always set the light, I had to read stored codes and coordinate the events when ESS didn't function.
It's a good indicator that something is wrong with the Jeep, IMO. If it's not working, something is wrong somewhere and it takes some digging to find it if there aren't any stored codes. Could be the temp sensors for the cats never get up to temperature, that would do it, ABS issues, and so on.
It's not always about batteries. (and it can be a main battery issue as well)
My testing has shown that during an auto stop/start event, even though disconnected from each other by the PCR being opened, they both drop voltage at a similar rate while it's stopped. If the aux battery was at 12.3, the main battery wasn't far behind.
I'm going to wire my own Jeep up again to do more tracking and recording of what goes on during such events, but I'm seeing that they have done an incredible job of splitting the load across both batteries during such a stop.

This is good advice, but……have you load tested your main battery? If your main is bad, it can drain your aux.

 

[Shibadog]

It sounds like your Jeep might qualify for the Lemon Law at this point? You have certainly given them enough attempts to repair.

Maybe @JeepCares can help?

It’s a 21 so lemon law has long since expiresd. I’d check ALL electrical plugs/fuses. I’d also put in the start/stop eliminator to bypass that stupid “ feature”?. I did it to mine right after I got it. Never a issue since.

 

[Under-Pressure]

It’s a 21 so lemon law has long since expiresd. I’d check ALL electrical plugs/fuses. I’d also put in the start/stop eliminator to bypass that stupid “ feature”?. I did it to mine right after I got it. Never a issue since.

It is still under the 3 / 36k warranty timeline & only has 6k miles. Should qualify.

 

[Shibadog]

It is still under the 3 / 36k warranty timeline & only has 6k miles. Should qualify.

Ossibly, but at least some areas are 12 month..

 

[Under-Pressure]

Ossibly, but at least some areas are 12 month..

I have never heard of 12 months for lemon law? Yikes! Dealers can waste that time easily.

 

[TrailScooter]

.....

I could use Roger Staubach and Drew Pearson right about now.

Alfonso

Tell me you're a boomer w/o telling me you're a boomer..

 

[andy29847]

Your trouble is most likely the main battery. The Jeep auto start system starts giving error messages around 12.4v. 12.4 volts is a battery at half-life by most standards. Obviously, your dealer does not understand the system.

I suggest getting a new main battery from Walmart. They have a H7 AGM battery that is 850CCA with a 4 year warranty. The Mopar batteries are 200cca for the small battery and either 600CCa or 700CCA for the main (depending on your option package).

Put in the new battery, disconnect and insulate the negative cable to the aux battery, pull fuse F42. All of your truck's features with operate as normal. I addition to that, with one battery the trucks battery system will operate just like cars have for the last 75 years.

 

[CMTAZ]

Main battery or the IBS. On my 20 Willy's it was the main battery.

 

[Bill_BCNtoNY]

Your trouble is most likely the main battery. The Jeep auto start system starts giving error messages around 12.4v. 12.4 volts is a battery at half-life by most standards. Obviously, your dealer does not understand the system.

I suggest getting a new main battery from Walmart. They have a H7 AGM battery that is 850CCA with a 4 year warranty. The Mopar batteries are 200cca for the small battery and either 600CCa or 700CCA for the main (depending on your option package).

Put in the new battery, disconnect and insulate the negative cable to the aux battery, pull fuse F42. All of your truck's features with operate as normal. I addition to that, with one battery the trucks battery system will operate just like cars have for the last 75 years.

this, or go all in and install a a genesis dual battery system (most likely overkill, expensive and effective in equal measure!)

 

[Mojofallen]

Tell me you're a boomer w/o telling me you're a boomer..

Actually I'm Gen X. But I was born and raised a Cowboy fan. And that play is one of the greatest in Cowboy's history.

 

[TrailScooter]

Actually I'm Gen X. But I was born and raised a Cowboy fan. And that play is one of the greatest in Cowboy's history.

Yeah, me too, I'm a young stud. No onion on my belt. ?

 

[DaltonGang]

Hook up a Trickle Charger and charge it overnight. If the ESS starts working again, its probably your batteries not getting fully charged. Short trips will not properly charge the batteries.

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