[Mark_]

<snip>
The local CarMax was booked up for the day, so no appointments available there to get them to replace the battery, but a very cute young lady there assured me that if I did it myself, they'd reimburse me the cost of the battery, so that's what I did.

Huh ? Very cute young lady and a free battery ?? Tell me where you live please, like right now ! (j/k... I think...)

 

[Mark_]

Like I said earlier [edit : oops, this was in another thread, sorry], running voltage can and will drop below 14V in hot weather, the system is designed that way. That said, if a battery is near death with a bad cell for example, this can effect charging for sure.

 

[Mark_]

I see that both batteries that AutoZone offers, that it says will fit this vehicle, are AGM. I took a picture of the old battery, just before I left it behind as a core, and I see that it says it's AGM as well. I'm pretty sure that was the original battery, that this car had from the factory.

Autozone must have done work on their fitment guide, because not that long ago they were still offering AGM and flooded options for ESS Cherokees. Just FYI, they have 4 different H7 options : regular flooded, Duralast Platinum EFB, Duralast Platinum AGM and the Yellow Top Optima AGM from Johnson Controls / Clarios. Autozone had the Odyssey AGM before (the best option) but I think they've dropped it. The Platinum EFB is an enhanced flooded battery, not as potent as an AGM. Your Yellow Top is definitely an AGM.

Edit ; do you have that picture of the old battery ? The original is easy to identify, and yes it is AGM.

 

[Mark_]

View attachment 233182

Yep, that is the original AGM. Mine was exactly the same (2015).

Edit. Well. almost identical... (mine was the 'AA' variation, yours is the 'AB') :

 

[Mark_]

So, just to be clear, what you seem to be saying is that even if there is nothing “wrong” with my Jeep, regarding the ASS system and anything that affects it, my Jeep can still occasionally throw this error if starting conditions are outside of some expected parameters, such as the door being open, or the steering position. That occasionally seeing this error is not a cause for concern.

Is this correct?

I'll throw in my 0.02. 'Service Stop/Start' is a head scratcher because it doesn't immediately point to any problem. When ESS is disabled because of a door open or steering angle, there is a clear message showing these. Same with cabin temperature, low fuel, low coolant temperature, battery charging, etc... the message is clear.

Anecdotally, 'Service Stop/Start' is often caused by an out of spec IBS, but that's not the only cause. We've seen this happen with (and my memory fails on some of them I'm sure - others please chime in) wheel sensor, ground strap, BCM and possibly more. In other words, it may not be easy to t-shoot at this point.

Also... from other reports on this forum similar to yours, I'd say this type of 'problem' hasn't been critical, not at all, meaning it's Ok to ignore, more or less. That's easy to say, especially to someone with a slight OCD not wanting error message in their face all the time, I get that (I'm kinda like that, but I cope better as I get older, heh).

What you need now : 1) a bit of luck, and/or 2) a tech capable of hunting this down. Or 3) Ignore and observe.

 

[Mark_]

Back when I thought I was going to get a Bronco, a few years ago, I paid a lot of attention to all the various proposed methods of disabling ASS. Most involved various ways of fooling it into thinking conditions existed under which ASS should not be activated. And nearly all involved adverse side effects of various sorts.

It seemed clear enough to me, then, that the ASS eliminator was by far the best solution. It doesn't do anything to trick the system into thinking some condition is different than it is, in any way that would adversely affect anything else about how the vehicle operates. The only foolery involved is in making the system think that the operator has pushed the button to properly disable ASS.

I'm a part-time ESS user. I know that may not make a lot of sense to some, but it's how I do things. Like @Flybynightcru , I now have it down as learned behavior to just push the dang button. Free and easy (for me). When I know I want an ESS stop, I just push the button again.

 

[Mark_]

I went looking for advice on another forum, and the hood switch came up. Seeing it mentioned once on one forum didn't really register on me, but seeing it mentioned elsewhere did.

So, I went out, opened my hood, and looked for the hood switch. Pushing it down with my finger, it felt stiffer than I thought it should be, and when I released it, it came up very slowly.

I tried spraying a bit of contact cleaner on it, and worked it up and down several times, and now it works much more freely, about how I think it should. Perhaps that was the problem, that the switch was dirty to the point that it didn't move freely, and that it needed to be cleaned/lubricated. I took my Jeep for a short, but vigorous test drive thereafter, and the ASS error didn't come up on that drive. I'll have to see if the problem comes back.

That would be awesome if it is the problem. Thx to @antpennino for stopping by with the suggestion.

 

[Mark_]

Can you easily disconnect the push-down switch ? I'd try that. Mine is a 2015 and the switch is different. (in a different spot anyway).

 

[Mark_]

So, the new hood switch has arrived, I've installed it, and I am still getting the ASS error.

I previously replaced the Intelligent Battery Sensor (IBS), and the battery itself.

Any other ideas?

I recently got the Haynes manual for this Jeep, and I have taken note that it demands that the IBS and the battery be disconnected in a particular order, which I did not know when I replaced the battery or the IBS. Could I have damaged the new IBS this way, and might I need too replace it again? Is there any way to test an IBS to determine whether it is good or not?

Hmmm. I've read that wiTECH can show if the IBS operates within specs, but not sure how that works exactly. If wiTECH can, maybe AlfaOBD can as well, I just can't confirm (because I don't use it myself).

 

[Mark_]

I may have spoken too soon... I did find this but there's no real way of knowing if this means it's being measured by the IBS or by some other means. Unfortunately my 2014 was pre-IBS so I have no way of testing this parameter.

View attachment 233767

Yeah maybe your sensorless 2014 doesn't have it in the firmware...

 

[Mark_]

Are you saying my 2014 doesn't have a lot of sense???

No. I'm saying it's not very sensitive

 

[Mark_]

According to a post I found (from this forum), the 2020 problematic relay is the Run/Start relay K9.

Source : https://www.jeepcherokeeclub.com/posts/2989214/

Pic of Star case : https://www.jeepcherokeeclub.com/posts/2959309/
(picture resolution is pretty good, I downloaded it and zoomed in so I could see it is relay K9 and there is an arrow pointing to it).