ESS still not working. Cold weather?

[lohr500]

Those of you following these pages will be aware of the ongoing saga with the ESS system on my JLU.

Last week the dealer finally fitted a new Aux battery and for the 1st few days, the ESS worked faultlessly.
But once again it has stopped. Despite a couple of 1 hour journeys this week, there has been no sign of the ESS kicking in.

I have tried driving with the lights, heater/air con /heated seats & wheel all switched off to minimise the current draw on the batteries but it made no difference.

I am now wondering if there is a parameter in the ESS logic that disables the ESS in cold weather.

Can anyone tell me if your ESS works at a displayed external temperature below 10 degrees C?

I have asked Jeep support in Italy if they can give me a list of the parameters used in the ESS logic, but I am not hopeful of a response.

Thanks

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[geem03]

I haven't noticed what temperature it stops working but yes, it will not activate in colder weather, from what I've seen. Sometimes if it does, it will only be for a few seconds then the vehicle starts up again. I do have the 6M though...

 

[WranglerMan]

One of the many things that affect ESS operation is if the cabin of the JL is heating or cooling so if it’s cold out and your temp setting is calling for heat ESS will not engage or it will disengage if it’s enabled

 

[Plasmadaddy]

My ESS works all the time even at very low temps. Lowest so far since I've had the Jeep has been 2 degrees and ESS starts to work very quickly (I actually turn it off most of the time anyway!)

My AC is set to 1 on the fan speed and 20 to 21 degrees on the temp.

 

[gbr]

ESS turns off at -14C, which is 6.8F

 

[lohr500]

Thanks gbr. We are nowhere near -12 right now. +7 or 8 where I am.

 

[BrntWS6]

My Jeep sits for 3-4 days a weeks amd when I do drive its generally only 15-30 min. It has taken 2hrs of driving to fully charge both batteries so the ESS will engage. Took it to the dealer to load test the batteries and both were fine. My solution was this:

https://www.jlwranglerforums.com/fo...arger-mount-inlet-install-lots-of-pics.44466/

 

[lohr500]

Thanks for the info BrntWS6.

I've reached the same conclusion.
Usually I do short journeys with several days of inactivity in between.

Last week I popped the Jeep on a boost charger for 12 hours and the ESS worked perfectly every time for several days thereafter, even with sub 8 deg Celsius external temperatures.

And then I did a return journey to London last weekend with 4 1/2 hours drive each way. The ESS has continued to work since.

It seems strange that the Jeep can't charge the batteries without a long run, especially as the UK Rubicon is supposed to have the heavy duty alternator fitted as standard.

I'm going to see how long the ESS keeps working before needing another boost charge.

 

[lohr500]

Well, with daily short journeys (less than 10 miles) it continued to work for just over a week, then stopped working again.
I popped it on an 8 amp max output smart charger this afternoon for only 4 hours and it is now back in action.

I've rigged up a short 12v lead from the charger which plugs into the 12v cigar socket in the rear load area.
The mains charger sits in the garage, with the 12v lead running outside.
There is probably some voltage drop due to the extended 12v lead, but it seemed to cope OK this afternoon charging the batteries.
When the 12v cigar plug is removed, I will put it inside an upturned glass jar to keep the rain off it.

It's now easy enough back up the Jeep next to the garage and then plug the lead into the cigar socket every now and then to top up the batteries.
Every time I plug it in I will tie a bit of ribbon round the steering wheel to remind me to disconnect it before driving off

 

[Dogboyslim]

ESS turns off at -14C, which is 6.8F

I have had it turn off at +2F after running for an hour and stopping at the bottom of the on-ramp. It only stayed off four about 5 seconds and restarted before the light changed. I only remember it because I was surprised it turned off. I've never had it turn off when <0 F, and other than this, I've never noticed it turn off at <5F. So I would guess that this info is reasonably accurate, even if there are some bizzare circumstances that are slightly different.

 

[UKJeep2018]

Sorry to bump such an old thread, but the ESS system is definitely weird in the Jeep.

My daily commute typically involves 10mins of motorway driving and 20mins of city driving. So I would have thought the battery would be well charged for ESS to be active? Instead it very rarely activates. So far I have gone 2 weeks without ESS working.

 

[lohr500]

I am afraid mine is still very much hit and miss. More often miss. If I charge the batteries manually overnight on the "high" 12A setting on my charger, then the ESS will work perfectly for 4 or 5 days. It kicks in once the engine starts to warm up and the temperature gauge hits around 1/4 on the scale. But then after a few days it stops working unless I charge the batteries again or go on a very long run (typically a couple of hours on the motorway). To be honest I can't be bothered having another lengthy debate with Jeep about it and being without the vehicle for days on end whilst they try to figure out why it doesn't work effectively.

 

[JLURUBI]

Sorry to bump such an old thread, but the ESS system is definitely weird in the Jeep.

My daily commute typically involves 10mins of motorway driving and 20mins of city driving. So I would have thought the battery would be well charged for ESS to be active? Instead it very rarely activates. So far I have gone 2 weeks without ESS working.

My 2018 was doing the same thing (I have about 10 min Highway and 10 min in town commute) Charging the batteries wouldn’t help, no warnings or dash lights and the dealer didn’t find anything. i continued to drive it for another month and I finally got A very helpful technician to help diagnose the problem. They replaced the alternator and both batteries. Everything worked fine until I sold it and ordered a Diesel 3 weeks ago

 

[UKJeep2018]

Took my Jeep to the dealer, and they found nothing wrong with it, they did suggest I book my jeep in for a day to get the batteries charged, but wouldn’t this issue just come back? That just sounds like a band-aid fix to me.

 

[lohr500]

Yep, band-aid fix

As I mentioned above, if I charge mine at home it will work for a few days, then stops. I have even rewired the front and rear dashcam power feeds so they are now ignition fed, rather than permanently live (with built in low voltage cut off units in the power supplies), but it made no difference.

I have also noticed in the cold weather now, that sometimes the engine doesn't start on the 1st press of the start button. The diesel glow plug light comes on for a few seconds, but then the engine doesn't crank over and the rev counter and speedo needles do a full sweep. On a second press of the start button it cranks over and starts. I suspect this is another indication of a low battery charge condition.

If the starting doesn't get worse I will leave it until the spring and then get it back to the dealers before the warranty runs out. If it needs new batteries and/or alternator, I would rather this gets done under warranty.

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