Auto Stop/Start Stopped working.

[ShadowsPapa]

Mine also stopped working for a few weeks now. Displaying Battery is charging, a sign of the aux battery is going out. I'm replacing it before it take out the main battery.

It's not always a sign the aux battery is going.
As discussed many times - could be the main battery is going, could be you don't drive it far enough, long enough, to keep the batteries charged above 12.4/12.5 volts.
The aux battery doesn't always "take out" the crank battery. It can go bad and not take out anything, or as at least a couple of forum members have found - it was their CRANK battery that was bad, not the aux battery.
There's a lot of assuming out there- and a lot of misinformation, assumptions and so on.

So what if you simply replace the aux battery, no charging, no testing, and two weeks later find both bad because it was really the main battery causing the issue, or it was really your not driving it enough to keep the batteries up?

I had that with my 2020 - I fully charged both batteries independently of each other, reset the IBS - and amazing, it worked a lot better. I wasn't driving it enough and far enough.

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[MojaveMat]

I had that with my 2020 - I fully charged both batteries independently of each other, reset the IBS - and amazing, it worked a lot better. I wasn't driving it enough and far enough.

Do you need to take it in to the Dealer to reset IBS or is that easy to do on your own?

I’m not having any issues or errors just finally realized it ESS hasn’t kicked on in a while. I don’t mind it just as long as there isn’t some other underlying issue. The ESS screen only says “Start/Stop Not Ready” doesn’t say anything about the battery. Someone mentioned it might not say that for the Aux?

 

[Vtur]

It's not always a sign the aux battery is going.
As discussed many times - could be the main battery is going, could be you don't drive it far enough, long enough, to keep the batteries charged above 12.4/12.5 volts.
The aux battery doesn't always "take out" the crank battery. It can go bad and not take out anything, or as at least a couple of forum members have found - it was their CRANK battery that was bad, not the aux battery.
There's a lot of assuming out there- and a lot of misinformation, assumptions and so on.

So what if you simply replace the aux battery, no charging, no testing, and two weeks later find both bad because it was really the main battery causing the issue, or it was really your not driving it enough to keep the batteries up?

I had that with my 2020 - I fully charged both batteries independently of each other, reset the IBS - and amazing, it worked a lot better. I wasn't driving it enough and far enough.

I did a quick checked when i was installing the Aux switch recently. I had both cables disconnected from the main battery, it had 12.6v but just 11.4v with the aux in the circuit. Also, when ESS were working, checking at the main usually shows above 12.5v.

Edit: i have a Yuasa YTX14-BS coming. Diesel comes with the 200CCA battery.

 

[Dougstdig]

Do you need to take it in to the Dealer to reset IBS or is that easy to do on your own?

I’m not having any issues or errors just finally realized it ESS hasn’t kicked on in a while. I don’t mind it just as long as there isn’t some other underlying issue. The ESS screen only says “Start/Stop Not Ready” doesn’t say anything about the battery. Someone mentioned it might not say that for the Aux?

Is your seat belt fastened? Not having it latched will prevent the ess engagement.

 

[wachuko]

This thread made me get a battery tender right away... arriving today and will install this afternoon.

 

[bjohnsonmn]

I'll say it... It is insane to me that a modern vehicle, costing more than $60k sticker, needs a battery tender to remain reliable. Yeah, I get that there are more parasitic draws from the factory. However, allowing a vehicle past the engineering phase with that as an acceptable condition is lazy and unethical.

There's a fundamental issue with the ESS/Auto Start/Stop system, the electrical system, or the design of the system as a whole that is leading to this. Perhaps it is time for a NHTSA case to be opened.

 

[ShadowsPapa]

There's a fundamental issue with the ESS/Auto Start/Stop system, the electrical system, or the design of the system as a whole that is leading to this. Perhaps it is time for a NHTSA case to be opened.

Seriously?? For what? It's not a safety issue. NHTSA is National Highway Traffic SAFETY.......... it's not a safety risk in any way, shape or form and most people don't even know there's a problem because it will keep on starting and keep on getting them to where they need to go.
It's another thing amplified by the internet and those tracking it closely.
We've had 4 or maybe it's 5 Jeeps with this system. Only one of them has failed to start - and that was 3 years in on a vehicle that got driven maybe once a week, at times it sat for 8 - 10 days.

Most issues actually happen after almost 3 years and at that - it's not life or death, it's annoying, and roughly at the end of life for the batteries anyway.

I'll say it... It is insane to me that a modern vehicle, costing more than $60k sticker, needs a battery tender to remain reliable. Yeah, I get that there are more parasitic draws from the factory. However, allowing a vehicle past the engineering phase with that as an acceptable condition is lazy and unethical.

Like so many other things - it takes time to find flaws. On the surface, it appears fine, and systems like this have been in cars ranging from Chevrolet, BMW and several others I have listed before. This is NOT a Jeep configuration. A few things may be unique in how they are handled, but the smaller aux battery wasn't invented by Jeep nor were they the first to use it.
My 2022 actually appears to charge differently than my 2020 did - so did they make a change seeing issues over time?
How do you find all flaws in a complex system in 1 year's time? Is your phone flawless? You've never ever had to reboot a router? Your internet has never gone down?

Most owners may realize the ESS has stopped functioning as about the only clue they are going to see battery needs in the future. For those that turn it off, there won't be clues until later when maybe the aux switches stop working. By that time - it's likely time for new batteries anyway - so is it a flawed system?
You want your fancy infotainment system. You want lights to come on as you approach or be able to lock or unlock it from 100 yards away, you want a WiFi hot spot, you want this and that but then expect batteries to last like a legacy car 30 years ago with the only parasitic draw being a fancy digital radio.

I don't have a tender on mine, it gets driven maybe 3 times a week, sometimes 2 times a week, and after 6 months, everything related to batteries and ESS is working just fine.
I have a feeling that some mods may have been made between the 2020 and 2022 model years. I can't prove it YET - but since I drive this one like I drove my prior JT, time will tell.
My 2020 was approaching 3 years before I started seeing anything going on, and that's only because I do use ESS and I was using it as an indicator of things. Once I charged each battery INDEPENDENTLY and reset the IBS - it went back to working fairly normally although the batteries did drop faster than when it was new. But then - that's the way it goes, that's how it works if you know the science of batteries in general and AGM specifically.
I bet had I kept that truck and put a new battery in at 3 years, I'd have gotten by longer.

Anyway, NHTSA won't give a rip about battery technology. It's a place for people to list gripes, but the feds won't see it as an issue. And frankly, of the tens of thousands of Jeeps sold the issues are not that common. They are amplified because forums and fakebook are like support groups for people with problems.
And since the Grand Cherokee has used this EXACT same system since 2016 - it's apparently not as big a thing as it appears. Not small by any means - it's quirky and could be a lot better (like monitoring and charging two very different sized batteries like each needs to be charged) but it's not a disaster, IMO. Absolutely needs work, yes, needs to be better, and part of that better would be bigger batteries!

 

[wachuko]

Funny... my wife jokes that I have electric vehicles since all of them are on battery tenders...

 

[bjohnsonmn]

Seriously?? For what? It's not a safety issue. NHTSA is National Highway Traffic SAFETY.......... it's not a safety risk in any way, shape or form and most people don't even know there's a problem because it will keep on starting and keep on getting them to where they need to go.
It's another thing amplified by the internet and those tracking it closely.
We've had 4 or maybe it's 5 Jeeps with this system. Only one of them has failed to start - and that was 3 years in on a vehicle that got driven maybe once a week, at times it sat for 8 - 10 days.

Most issues actually happen after almost 3 years and at that - it's not life or death, it's annoying, and roughly at the end of life for the batteries anyway.



Like so many other things - it takes time to find flaws. On the surface, it appears fine, and systems like this have been in cars ranging from Chevrolet, BMW and several others I have listed before. This is NOT a Jeep configuration. A few things may be unique in how they are handled, but the smaller aux battery wasn't invented by Jeep nor were they the first to use it.
My 2022 actually appears to charge differently than my 2020 did - so did they make a change seeing issues over time?
How do you find all flaws in a complex system in 1 year's time? Is your phone flawless? You've never ever had to reboot a router? Your internet has never gone down?

Most owners may realize the ESS has stopped functioning as about the only clue they are going to see battery needs in the future. For those that turn it off, there won't be clues until later when maybe the aux switches stop working. By that time - it's likely time for new batteries anyway - so is it a flawed system?
You want your fancy infotainment system. You want lights to come on as you approach or be able to lock or unlock it from 100 yards away, you want a WiFi hot spot, you want this and that but then expect batteries to last like a legacy car 30 years ago with the only parasitic draw being a fancy digital radio.

I don't have a tender on mine, it gets driven maybe 3 times a week, sometimes 2 times a week, and after 6 months, everything related to batteries and ESS is working just fine.
I have a feeling that some mods may have been made between the 2020 and 2022 model years. I can't prove it YET - but since I drive this one like I drove my prior JT, time will tell.
My 2020 was approaching 3 years before I started seeing anything going on, and that's only because I do use ESS and I was using it as an indicator of things. Once I charged each battery INDEPENDENTLY and reset the IBS - it went back to working fairly normally although the batteries did drop faster than when it was new. But then - that's the way it goes, that's how it works if you know the science of batteries in general and AGM specifically.
I bet had I kept that truck and put a new battery in at 3 years, I'd have gotten by longer.

Anyway, NHTSA won't give a rip about battery technology. It's a place for people to list gripes, but the feds won't see it as an issue. And frankly, of the tens of thousands of Jeeps sold the issues are not that common. They are amplified because forums and fakebook are like support groups for people with problems.
And since the Grand Cherokee has used this EXACT same system since 2016 - it's apparently not as big a thing as it appears. Not small by any means - it's quirky and could be a lot better (like monitoring and charging two very different sized batteries like each needs to be charged) but it's not a disaster, IMO. Absolutely needs work, yes, needs to be better, and part of that better would be bigger batteries!

Sure.
NHTSA has a history of approving programs that increase the risk of strandings as well as cascading issues. I've had one battery go bad, but they also had to replace the TIPM related to the ESS/Auto Start/Stop. And, it is more than simple social media amplification. It is in my own social circle of fellow Jeep owners.
While the system has existed in other vehicles, the application of it in ours is new.

Also, you are right, it does take time. FCA/Stelantis has recalled things that emerge over time that have a lower level of occurrence than this with less severity. Even Warn is recalling winch remotes due to accidental engagement from water damaged controllers. I can see how a winch line around the axle is a safety issue, even for the very few reports of accidental activations that have been reported.

Your reply comes off defensive of Jeep and not all that helpful. There's no need for that. I'm a proud owner and refer people to Jeep brand vehicles regularly. There's no need to white knight for them on a Jeep owner forum.

 

[sharpsicle]

Sure.
NHTSA has a history of approving programs that increase the risk of strandings as well as cascading issues. I've had one battery go bad, but they also had to replace the TIPM related to the ESS/Auto Start/Stop. And, it is more than simple social media amplification. It is in my own social circle of fellow Jeep owners.
While the system has existed in other vehicles, the application of it in ours is new.

Also, you are right, it does take time. FCA/Stelantis has recalled things that emerge over time that have a lower level of occurrence than this with less severity. Even Warn is recalling winch remotes due to accidental engagement from water damaged controllers. I can see how a winch line around the axle is a safety issue, even for the very few reports of accidental activations that have been reported.

Your reply comes off defensive of Jeep and not all that helpful. There's no need for that. I'm a proud owner and refer people to Jeep brand vehicles regularly. There's no need to white knight for them on a Jeep owner forum.

Funny, I was just thinking that your first post came off as overly-aggressive and exaggerated. Also not very helpful. Perhaps that's why you got the response you did?

 

[MojaveMat]

Hey guys, FYI just took my truck in bc the start/stop has been in “not ready” state for a couple months, no lights.

They thought it would be the batteries as that’s been the common cause, so they replaced all of those and still not working. The master mechanic was in so he was the one working on it.

He determined it was electrical wiring related and traced it back a corroded wire (they called it something else) in the core grouping of wires near the back of the truck. They fixed that and now it’s working again! So, if anyone is still having issues even after the battery replacements it could be something similar! ?

 

[ShadowsPapa]

Sure.
NHTSA has a history of approving programs that increase the risk of strandings as well as cascading issues. I've had one battery go bad, but they also had to replace the TIPM related to the ESS/Auto Start/Stop. And, it is more than simple social media amplification. It is in my own social circle of fellow Jeep owners.
While the system has existed in other vehicles, the application of it in ours is new.

Also, you are right, it does take time. FCA/Stelantis has recalled things that emerge over time that have a lower level of occurrence than this with less severity. Even Warn is recalling winch remotes due to accidental engagement from water damaged controllers. I can see how a winch line around the axle is a safety issue, even for the very few reports of accidental activations that have been reported.

Your reply comes off defensive of Jeep and not all that helpful. There's no need for that. I'm a proud owner and refer people to Jeep brand vehicles regularly. There's no need to white knight for them on a Jeep owner forum.

Not defensive of them at all other than stating the fact that people blame Jeep for the system as if it's a Jeep failing - maybe the implementation is - but they didn't invent it, nor are they the only company to use it or having used it.

NHTSA doesn't approve anything related to this sort of thing. They couldn't care less about a charging system or batteries unless there is a risk to health and safety - like a risk of fire or a vehicle abruptly stopping in traffic.
This Auto Stop/Start has existed for decades and is more related to EPA than NHTSA who doesn't have any hand in approving or not approving many vehicle systems. If they had to approve everything in a vehicle, they'd have more employees than the IRS.

Unless you have issues with these within the first couple of years, it's more of a "it's getting old" and the batteries have been cycled and have lost capacity thing - which plays into not holding up under parasitic draw.
If there's a problem within 2 years - that's when I'd start jumping at Jeep, but as they age........... these aren't your grandfather's vehicles. Don't expect 5+ years out of batteries today.
Heck the batteries in our huge UPS units at work didn't last that long! (and they were in a climate controlled room)

I look at these things from a tech standpoint - pattern recognition, puzzle solving, solutions, design and so on.

 

[ShadowsPapa]

Hey guys, FYI just took my truck in bc the start/stop has been in “not ready” state for a couple months, no lights.

They thought it would be the batteries as that’s been the common cause, so they replaced all of those and still not working. The master mechanic was in so he was the one working on it.

He determined it was electrical wiring related and traced it back a corroded wire (they called it something else) in the core grouping of wires near the back of the truck. They fixed that and now it’s working again! So, if anyone is still having issues even after the battery replacements it could be something similar! ?

Do you mean rear of the cab, inside right rear area?
Or the rear rear of the truck?
Asking to sort of try to think through "what might be there" that is in play with ESS.
In the rear of the cab is the BCM.
Behind the cab is the fuel system wiring and other nifty stuff.

These have a long list of over 20 items that must fall into line before ESS will operate and that does not include engine related things the PCM tracks - so likely we're talking over 100 things and you won't get a message on any of those except a handful - HVAC- cabin cooling/heating, steering column angle, outside temperature too hot or too cold you'll get messages but most of the rest, no message.

Sounds like you got a guy who cared and knows his stuff.

It's not always about batteries.

 

[Mojave2021]

FWIW I recently had this issue and the aux battery was determined to be defective by my dealer. After replacing the aux battery I have not seen this issue again and it has been about 6 months now. I haven't needed to keep it on a tender either. If I am not driving my cars on a weekly basis I do use a tender for them.

 

[MojaveMat]

Do you mean rear of the cab, inside right rear area?
Or the rear rear of the truck?
Asking to sort of try to think through "what might be there" that is in play with ESS.
In the rear of the cab is the BCM.
Behind the cab is the fuel system wiring and other nifty stuff.

These have a long list of over 20 items that must fall into line before ESS will operate and that does not include engine related things the PCM tracks - so likely we're talking over 100 things and you won't get a message on any of those except a handful - HVAC- cabin cooling/heating, steering column angle, outside temperature too hot or too cold you'll get messages but most of the rest, no message.

Sounds like you got a guy who cared and knows his stuff.

It's not always about batteries.

yeah, seems like I got lucky I had someone who knew what they were doing. They had to trace all of the wires and connections. I’m not entirely sure which one it was but they said there is a core grouping of wires that run the length of the truck like a spinal cord and it was one of the wires in that bundle near the rear they had to repair. Start/stop was the only thing not working at the time (that I knew of). The strange thing is when they first replaced all of the batteries and IBS the Avenger light finally came on; prior to I had no lights.

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