ESS and power loss

[Rogue321]

Hi. I'm new to the forum. I've got some JLU woes. Several, actually.

One of them being sometimes my ESS (that's the auto start/stop, right?) light comes on and the Jeep doesn't have the same power. A simple turn off and back on remedies the issue. Today I felt the engine hiccup while driving, ESS light comes on, and there is a slight but noticeable power loss.

I searched but didn't see anything related to this. I don't even know what the ESS would have to do with power and certainly don't know why it would turn after feeling an engine hiccup.

Any thoughts?

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[LarryB]

Hi. I'm new to the forum. I've got some JLU woes. Several, actually.

One of them being sometimes my ESS (that's the auto start/stop, right?) light comes on and the Jeep doesn't have the same power. A simple turn off and back on remedies the issue. Today I felt the engine hiccup while driving, ESS light comes on, and there is a slight but noticeable power loss.

I searched but didn't see anything related to this. I don't even know what the ESS would have to do with power and certainly don't know why it would turn after feeling an engine hiccup.

Any thoughts?

When you say “ESS light,” are you referring to the A with the circle around it, like the Avengers logo or are you talking about a warning light of some kind? Is the Jeep throwing any error codes?

One thought (I am far from an expert) … if your alternator was having issues, it would have problems charging your AUX battery (as well as other issues) and that could be related to a lack of power. However, not sure that would be fixed by powering off/on the engine.

Did you seat all of your fuses on the Jeep? I had a couple of electrical gremlins at first and this helped.

My last thought was a bad ESS (Aux) battery, but that usually has some different symptoms.

i would definitely get it looked at, especially if you are close to the end of your warranty.

 

[Jebiruph]

Check the cables on the negative battery terminal, sometimes they work loose.

 

[Rogue321]

When you say “ESS light,” are you referring to the A with the circle around it, like the Avengers logo or are you talking about a warning light of some kind? Is the Jeep throwing any error codes?

One thought (I am far from an expert) … if your alternator was having issues, it would have problems charging your AUX battery (as well as other issues) and that could be related to a lack of power. However, not sure that would be fixed by powering off/on the engine.

Did you seat all of your fuses on the Jeep? I had a couple of electrical gremlins at first and this helped.

My last thought was a bad ESS (Aux) battery, but that usually has some different symptoms.

i would definitely get it looked at, especially if you are close to the end of your warranty.

Thanks.

Yep, the A with the circle around it. I have no codes.

I've read a lot about that light being a problem, but never associated with a power loss. I was hoping someone might have experienced it knew that might be the case.

I'll reset all the fuses. I've got a few gremlins as well.

 

[Rogue321]

Check the cables on the negative battery terminal, sometimes they work loose.

Main battery or auxiliary battery? Or both?

 

[WranglerMan]

Your best bet when tightening terminals on batteries is to use a torque wrench and tighten to 50-70” lbs as it will keep you out of trouble, lots gets mechanical tight and electrical tight confused.

The terminals on the JL especially the one thats on the main battery are not heavy duty and does not take much to damage, the bolt on the negative terminal is really cheap and does not take much to break when over tightened.

If they have been over tightened to the point where there is no gap between the ears of the terminals you can loosen and add battery post shims instead of trying to bend the ears back on the terminals risking breaking them then you will be left to replace the cable.

 

[Gee-pah]

@Rogue321 James: a good read on the use of trickle charging to sometime bring older batteries to their best performance or simply keep ESS running.

https://www.jlwranglerforums.com/forum/threads/ess-problems-need-input.76146/

The thread also talks about how to take individual voltages of each battery, which BTW is a diagnostic tool better at identifying bad, not good batteries.

In other words you may get good voltages but a load test, which determines a batteries ability to take and delivery a charge, may reveal batteries in need of replacement.

 

[Rogue321]

Your best bet when tightening terminals on batteries is to use a torque wrench and tighten to 50-70” lbs as it will keep you out of trouble, lots gets mechanical tight and electrical tight confused.

The terminals on the JL especially the one thats on the main battery are not heavy duty and does not take much to damage, the bolt on the negative terminal is really cheap and does not take much to break when over tightened.

If they have been over tightened to the point where there is no gap between the ears of the terminals you can loosen and add battery post shims instead of trying to bend the ears back on the terminals risking breaking them then you will be left to replace the cable.

I tightened the terminals. It didn't help and the light is coming on more and more frequently.

That in itself isn't so bad, but the power loss is a pain.

 

[Jebiruph]

I tightened the terminals. It didn't help and the light is coming on more and more frequently.

That in itself isn't so bad, but the power loss is a pain.

What is the voltage reading during the power loss?

 

[WranglerMan]

I tightened the terminals. It didn't help and the light is coming on more and more frequently.

That in itself isn't so bad, but the power loss is a pain.

Have the batteries been fully charged and both checked with a reliable meter, especially after tightening up the battery connectors, as most here know ESS will not function correctly with the baby battery undercharged or bad and if both are undercharged or going bad all sorts of bad things happen with the Limp mode.

The whole design by FCA is terrible but we all know that, at this point I would check both batteries to ensure they are charged and holding a charge and replace if needed, being a 2018 if they are original batteries they most likely are at the end of there life especially if they have not been maintained and if they do indeed need replacing I would go a different route than what was originally installed.

The while regenerative charging or Smart charging as they call it is wonderful on the Engineers desk but in real life it’s a joke and I would rather go back to a constant charge being thrown all the time to one battery but alas we must keep the world safe by saving a gallon or two of gas with ESS

 

[Friday2322]

I have a 2018 and dropped it off at the dealership because about a week ago the message panel popped up with a message saying the ESS was not available. I got a call a little while ago from the service manager saying that the small battery was fine but the IBS (intelligent battery sensor?) had melted and they were having to order a new one. This is the first issue I've had with my batteries so I'm hoping it's not the start of something bad.

 

[skleiner]

Mine just always tells me the battery isn't ready because no charge!!

 

[Rogue321]

What is the voltage reading during the power loss?

Good question. I haven't thought to look.

That said, I can turn the Jeep off and back on and problem is gone.

 

[mwilk012]

It’s been 3 years and everyone is still confused about what ESS is. ANY warning light coming on is a problem that needs to be fixed. If you’re under warranty, get to the dealer.

 

[Rogue321]

What is the voltage reading during the power loss?

14.3, same as when normal.

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