ESS question (yup, another one)

[plisken]

In the past I had ESS issues with the 2.0T which the dealer eventually resolved by replacing the aux battery. I now have a 2.2 diesel Rubicon and the Stop/Start isn't working. No errors, just not working. As a point of note, the UK models do not have a menu option to show the status of the ESS, I learned that during my previous encounters, so it's not as simple as just checking that screen.

I was wondering if somehow the system has been deleted or tricked into not working. The disable ESS button does nothing apart from illuminate when pressed. I can't remember if my previous Rubicon displayed some sort of ESS system enabled/disabled when toggling this button or not?

Anyway, I thought I'd disconnect the bonnet (hood) switch, the right most one as that was sure to illuminate the ESS fault light and a message along the lines of Stop/Start system needs service or similar. However when doing this on my current Jeep (2019 2.2 Rubicon) there was no light or message, but the Check Engine Light came on. With the switch reconnected and everything back to normal, the light went out after a few journeys.

So I'm in a bit of a pickle, as I fully expected this pin switch to do what it's done before on my previous Jeep as also as reported all over the internet but this is not the case here.

Voltage when driving is around 13.8/13.9, maybe a bit lower if I start to load up with lights and blower.

I dont want to jump in and change the aux battery without getting the fault showing and the fact the Check Engine light comes on when disconnecting this pin switch is concerning.

Any thoughts?

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[calemasters]

I have a 3.0 L JLURD and I replaced both batteries for a reason not related to ESS. So this eliminates battery realated ESS issues. Being in the USA, I do have a menu option to show the status of the ESS. I found it Interesting that about 90% of the time, while driving in the city, the ESS status is "Not Ready". Personally, I find ESS useless and annoying.

I wonder if your ESS is OK, but the Jeep does not meet all of the requirements for ESS to go into the "ESS Ready" status? See requirements below:

 Driver’s seat belt is not buckled.
 Driver’s door is not closed.
 Battery temperature is too warm or cold.
 Battery charge is low.
 The vehicle is on a steep grade.
 Cabin heating or cooling is in process and an
acceptable cabin temperature has not been
achieved.
 Gear selector in MANUAL (M) mode.
 HVAC is set to full defrost mode at a high
blower speed.
 HVAC set to MAX A/C.
 Engine has not reached normal operating
temperature.
 Engine temperature too high.
 The transmission is not in a forward gear.
 Hood is open.
 Transfer case is in 4WD Low or N (Neutral).
 Brake pedal is not pressed with sufficient
pressure.
 Accelerator pedal input.
 Vehicle speed threshold not achieved from
previous auto-stop.
 Steering angle beyond threshold (ESS
Models Only).
 ACC is on and speed is set.
 Vehicle is at high altitude.
 System fault present.
It may be possible for the vehicle to be driven
several times without the Stop/Start system
going into a STOP/START READY state under
more extreme conditions of the items listed
above.

 

[aldo98229]

I replaced both batteries on my 2018 Sahara V6 two years ago. I was getting the “ESS Unavailable” message along with a variety of other intermittent electronic gremlins. Replacing both batteries solved all the issues.

ESS works like charm now, but only if I drive the Jeep at least three times a week. If the Jeep sits in the garage for 3 or more days, the ESS won’t kick in for at least 30 minutes. If I don’t drive the Jeep for 2 weeks, ESS won’t kick in for at least 1 hour, while the batteries fully recharge.

Not sure how often you drive your Jeep, but this might be the issue if you don’t drive it daily.

Good luck.

 

[plisken]

Read the codes earlier and its showing only p152e which apparently is the hood switch 2. Now I'm unsure if the code reader is still showing the code as a historical error code or if it is still a fault. The Check Engine light has went out after a few journeys but of course the ESS is still not working.

At this stage I'm still confused as to why this Jeep brings the Check Engine light on when this switch is disconnected buy my previous JL brought the Stop/Start requires service light on. I find this stuff interesting and sore at the same time.

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