Top Reasons for ESS failure

[AucturitasJones]

Biscuit: you're rude and you misread. I didn't ask why, at my, say, first traffic light 30 seconds from my home the ESS didn't engage. I'm well aware of many of the factors that would have the ESS not kick in, from engine temperature, to battery voltage, to operational of the air conditioning on high, etc. In fact I discuss this in my post immediately above and explain the problem in my first post adequately enough for others to understand. This is the OPPOSITE of a broken ESS I describe. It's a vey much working ESS that's detected conditions not suited to its engaging at a vehicle stop.

Maybe I didn't make myself clear. Another poster had your suggestion but he didn't put the stupidity on me.

I'm asking why the vehicle turned the ESS error light on, on the dashboard, 5 seconds after turning over the rig.

There is a difference between a working ESS system, that doesn't engage because, say, the engine is cold, and which doesn't display an ESS failure light on the dash because the ESS IS working--in fact it's working enough to know it shouldn't engage yet--and a broken ESS system that displays a diagnostic on the dash.

The problem ended up going away. Maybe it was low ESS battery voltage that charged with enough road mileage. The rig's diagnostic screens showed 14.4V, but that could have been on the main battery only. I don't know which voltage(s) are shown on the dash.

Hi. My Jeep is in the shop because this has happened a couple times and then it "stuck" on as an issue yesterday. I checked the battery which was stuck at 12.5 vdc instead of 13.7 vdc. When I checked the ESS messages (#6 screen in the garage cluster) it said battery protection mode. I hit the UConnect assist button on the mirror and the rep thought it could be the auxiliary battery. There are two batteries because it the ESS. If the extra battery overheats or goes bad it can cause the ESS to give an error. I dropped her off this morning at the dealer to get looked at.

I'm guessing you are still under warranty, so take her in and get it fixed before she strands you on the side of the road. Good luck!

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[RussJeep1]

Hi. My Jeep is in the shop because this has happened a couple times and then it "stuck" on as an issue yesterday. I checked the battery which was stuck at 12.5 vdc instead of 13.7 vdc. When I checked the ESS messages (#6 screen in the garage cluster) it said battery protection mode. I hit the UConnect assist button on the mirror and the rep thought it could be the auxiliary battery. There are two batteries because it the ESS. If the extra battery overheats or goes bad it can cause the ESS to give an error. I dropped her off this morning at the dealer to get looked at.

I'm guessing you are still under warranty, so take her in and get it fixed before she strands you on the side of the road. Good luck!

Thanks for the thoughts Jason. I cancelled the appointment I made with the dealer when the problem went away. Listening to your tale of woes I'm now thinking maybe I should not have.

My rationale was that if the problem went away, maybe the risk of getting a mechanic who doesn't even know about the second battery (thanks for bringing it up : I'm all to aware) wasn't worth the dealer trying to fix a problem that wasn't even manifesting itself, and screwing up even more, like blowing the main fuses in the PDS (Power Distribution System) as per Brandon Halon's YouTube videos on the subject matter.

It's the stuff jokes are made of. "What's the difference between an FCA mechanic on a new rig, and the mechanic down the block?"

"The FCA mechanic has people at FCA he can contact to teach him some of the things we already know as owners."

And that isn't to say that there aren't some fine mechanics at FCA like Brandon Halon. It is to say that Murphy's Law sticks to me like flies to poop, and I won't get one.

 

[Justarose]

I tool mine in for this same error light. I have the JLU 6 speed Manual Rubicon. It turned out to be bad Clutch Solenoid switch according to the paperwork from the service department. The part took 10 days to get in and now I have to wait till the 22nd for my local service department to get it in.

 

[RussJeep1]

I tool mine in for this same error light. I have the JLU 6 speed Manual Rubicon. It turned out to be bad Clutch Solenoid switch according to the paperwork from the service department. The part took 10 days to get in and now I have to wait till the 22nd for my local service department to get it in.

"It turned out to *seem* to be a bad Cluch Solenoid," Crystal, I say tongue-in-cheek as the jury's still out on this for certain being the problem and well, with my luck, repairs take 3.75 visits to remedy.

Thanks for sharing. This ESS is a pain and I'm in the camp that doesn't even mind it when it works right. The two batteries, the jump starting issues, the problems when it goes haywire....

the problems down the road when "the little engine, (err battery) that could" no longer can due to time and cold weather...

 

[Jebiruph]

Thanks for the thoughts Jason. I cancelled the appointment I made with the dealer when the problem went away. Listening to your tale of woes I'm now thinking maybe I should not have.

I'd take it in even if it's working now, they should be able to scan for a code as to why it failed. And the mechanics have to train on someones jeep.

 

[RussJeep1]

I'd take it in even if it's working now, they should be able to scan for a code as to why it failed. And the mechanics have to train on someones jeep.

I'll consider rescheduling on your first point @Jebiruph , if not your second.

 

[$uicide$hift]

I'll consider rescheduling on your first point @Jebiruph , if not your second.

Have you gone through and pushed down on all fuses and relays? If the relay that opens / closes the circuit to the ESS battery is getting intermittent contact it could explain the issue if and I say IF the ESS battery was low.

I would make sure all are seated good and then see if the error shows again. If it does I would make the appointment.

 

[RussJeep1]

Have you gone through and pushed down on all fuses and relays? If the relay that opens / closes the circuit to the ESS battery is getting intermittent contact it could explain the issue if and I say IF the ESS battery was low.

I would make sure all are seated good and then see if the error shows again. If it does I would make the appointment.

Thanks Jeff. Your idea sounds like time well spent.

 

[Aclud4]

in addition to the battery voltage issue which seems to be the cause for a large segment of owners experiencing this issue the 2nd most common issue is a faulty door wiring latch usually present on driver side front in the jlu

to test if you have this problem. disconnect the door wiring harness connectors as you would if you were going to take the doors off. start the engine. if the warning goes away and ess functions normally you have one of the faulty harnesses. your dealership can also confirm this error code to the door wiring harness latch.

@turk do you have any other info on this issue? Curious if it could be related to my intermittent issue where the Jeep won’t move to the off position. Been trying to reproduce it myself and the Jeep has been at the dealer since Wednesday over it. I’m to the point that I think it is related to timing of a seatbelt and/or door being opened prior to shutting off the Jeep. Any info you have on this issue would be great - I didn’t come across anything with a quick search.

Edit: Found this one: https://www.jlwranglerforums.com/fo...ght-and-auto-park-disabled.10982/#post-319064

 

[Shots]

I'm not going to argue with anyone about any of this, because I"m not a certified FCA mechanic. Like most of you probably are doing, I'm making assumptions about how it's supposed to work. Sure I may be wrong. I'm not going to imply that I know for sure why the light will/won't turn on.
I guessed, based on Biscuit's plausible theory. Admittedly it could be wrong, but maybe not.
Should it display the warning lamp in any condition, under some conditions, or under no conditions? Beats me, I'm not privy to that information, as I assume none of you are either. Maybe you're right..... maybe.

That said, I'll elaborate on why I thought Biscuit's theory made sense.
I tried the hood sensor trick to turn off ESS when I first bought the Jeep. The warning lamp and message displayed on start up with the sensor disconnected. As several of you have said, it's due to a "fault" in the system. Which makes sense, it should display when there's a fault. In the hood sensor being unplugged scenario, the computer reports an issue with the sensor because it's not receiving a signal. The computer isn't just reading that the hood wasn't closed, but that the sensor had failed. Hence the lamp and message on start up.
Going a step further, I tried to clear the sensor fault while still telling the Jeep the hood was open. To do this I simply took the sensor out of it's bracket and plugged it back in. After doing that the message didn't display and the lamp didn't turn on at start up. I drove around town like that with no ESS or message/lamp for quite some time. Exactly as we expect a working system to behave. However once I exceeded 30 mph the message displayed and the lamp turned on. This is the same after every restart (no message/lamp unless 30 mph is exceeded). On an unrelated note I put it back, because I don't dislike ESS that much. I just push the button to turn it off if I don't want it active
The point is ESS wasn't malfunctioning and the warning/lamp displayed. It was working exactly as it's designed to do. The hood is sensed as not latched, so the ESS doesn't engage. There were no faults triggered because everything was still connected. Yet the message and lamp both turned on, despite a WORKING system.

Since I know from actually testing it, the message and lamp displayed on my working system, maybe specific conditions will trigger the message/lamp while others don't. Then again maybe not. I don't know, I don't have FCA's manuals to tell me if it will or not. I'm only saying that instead of assuming Biscuit was being a jerk, maybe he was simply offering a POSSIBLE cause. Likewise, I commented, because I know my working system gave a message/lamp under different conditions and it seems logical that a low temp COULD have a similar result.

That't not to say there isn't a fault with the OP's ESS. There could be, but maybe there's not. If it was me and I thought there might be an issue, I'd get it looked at by a FCA mechanic. That's why we buy new cars with warranties, isn't it?

 

[RussJeep1]

"However once I exceeded 30 mph the message displayed and the lamp turned on."​

@Shots : Winchell...so the rig didn't like that the engine's speed was....(said with pinky at cheek) charging the batteries?!

I see your point on properly gleaning meaning from the ESS diagnostic light appearing in the dash as a reflection to the owner of a possible malfunction in the system and/or a properly functioning system's inability to "talk" to all it's inputs (e.g. the 2nd hood latch sensor) to properly form an "opinion" on whether ESS should engage at stops.

"I'm only saying that instead of assuming Biscuit was being a jerk, maybe he was simply offering a POSSIBLE cause"

On this Winchell we respectfully disagree. I mean it's not the end of the world: people say silly things (myself included) now and then, but you sell yourself short and him long.

Biscuit said, in no uncertain terms, that the diagnostic light came on because the engine wasn't warm yet, and intimated this to be knowledge of those who RTMF over asking others to do it or them. (RTFM: read the f_ manual.)

The ESS just doesn't (isn't suppose to) work that way. Rather, it will, working properly, as you know, neither throw a diagnostic code nor engage due to a cold engine.

Thanks for you input, which does make perfect sense, on how an ESS with zero logic problems could throw a diagnostic code out to say, "I'm incapable of speaking with all my sensors to form an accurate opinion on engaging ESS, and therefore correctly informing the driver as such."

"That's why we buy new cars with warranties, isn't it? "

True, but if only (tongue-in-cheek) I could buy the warranty that has my dealer, with 10 minutes notice, drive two vehicles to me, one an identical but working backup of my failed rig (kind of like there being two identical Boeing 747s for the President to use) and have that driver return to the dealer in the other rig: a flat bed tow truck that tows my failed rig, only to reverse the process when it's repaired.

Or to say, despite the warranty and the extended one I purchased, repairs are still a hassle: if not by any means exclusive to FCA, or something as a new model year purchaser with my eyes open, I didn't in part and in fairness to facts sign up for.

 

[Shots]

Yeah, I certainly agree that taking the Jeep in for service is rarely the ideal choice. Ultimately we buy new cars because we don't want to deal with problems, so any time it has to go for service it's bad. I guess the new cars with warranties is the safety net, not the go to. I'm certainly not faulting the OP for asking the question, because I think most of us here will try to address an easy fix ourselves rather than take it in. I know I would.

And I guess you are also possibly correct that I tend to give people the benefit of the doubt so would hope Biscuit wasn't trying to be rude. Although I suppose you never really know a person's true intent or tone on the internet.
For example it still blows my mind that there isn't a font, or text style that signifies sarcasm. Everyone seems to understand that all caps implies yelling, why do we not have a way to covey sarcasm in text? Oh well, completely off topic, but just an example of how things can be taken wrong online.

 

[Jebiruph]

Going a step further, I tried to clear the sensor fault while still telling the Jeep the hood was open. To do this I simply took the sensor out of it's bracket and plugged it back in. After doing that the message didn't display and the lamp didn't turn on at start up. I drove around town like that with no ESS or message/lamp for quite some time. Exactly as we expect a working system to behave. However once I exceeded 30 mph the message displayed and the lamp turned on. This is the same after every restart (no message/lamp unless 30 mph is exceeded). On an unrelated note I put it back, because I don't dislike ESS that much. I just push the button to turn it off if I don't want it active
The point is ESS wasn't malfunctioning and the warning/lamp displayed. It was working exactly as it's designed to do. The hood is sensed as not latched, so the ESS doesn't engage. There were no faults triggered because everything was still connected. Yet the message and lamp both turned on, despite a WORKING system.

The system is detecting the hood is open and you are driving 30 mph, two things that shouldn't happen at the same time. The warning lamp is indicating a possible defective hood switch.

 

[Shots]

That makes sense. Driving 30+ with the hood open would certainly be bad.

 

[Francois_Pipes]

I got A good one for you guys. My engine only shuts off when my doors are off. When my doors are on the feature does not work

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