ESS not working with relatively new batteries.

[Riperoo]

I really cant believe that I am complaining about this, but my ESS has suddenly stopped working, both of my batteries are about a year old, so I am stumped, even when I turn off the ESS, and you would normally have the lit "A" on the dash it shows nothing. Like I said, I hate to complain as I can't stand ESS, but I am worried there might be a gremlin somewhere waiting to pounce. Seems to have started in the deep of the cold winter so I wrote it off for a bit as I know there are a ton of parameters that have to be made for ESS to work, and various temps are a lot of them, but its been mild all week, I am doing a ton of driving and its still MIA. Appreciate any input on things to look at. I would be shocked if my batteries, main or Aux or bad but that is my next step to pull them and test. TIA.

Sponsored

 

[WillysMeow]

That's a nice 'feature' to have not working.

 

[Ratbert]

In my case it was a significant clue that my BMS had failed. Paying attention to it's absence is an early warning feature.

 

[Spacenut]

Bought my Rubicon used and ESS never worked until this winter when I hooked up a battery tender. It worked for the first time. Now with no tender and driving once a week or so it went away again.

 

[Riperoo]

In my case it was a significant clue that my BMS had failed. Paying attention to it's absence is an early warning feature.

Interesting, what was the eventual fix?

 

[Riperoo]

Bought my Rubicon used and ESS never worked until this winter when I hooked up a battery tender. It worked for the first time. Now with no tender and driving once a week or so it went away again.

I read that somewhere else as well, I'm gonna give that a try just to rule some stuff out! Thanks!

 

[roaniecowpony]

What is the battery voltage? Use a multimeter. ESS has a minimum threshold for voltage. If it's not at or above that threshold, it won't allow ESS. As Ratbert pointed out, ESS not working can be an indication of other issues.

I'm currently chasing a low voltage charging problem with my JLUR. I replaced the Intelligent Battery Monitor, no joy. I believe the voltage regulator is in the PCM.

 

[Ratbert]

Interesting, what was the eventual fix?

Replaced the BMS. That was covered by the warranty.

 

[THAW]

FYI, ESS will be disabled and the ESS display on the EVIC will show "Stop/Start Not Ready" anytime the IBS SOC is below 65% (obviously the display message will indicate more specific information when conditions warrant).

 

[Bob Burd]

To start, you can check the EVIC display to see the state of ESS.
Failing that, get JSCAN and an OBDII reader, pay $25 for the Wrangler specific extended checks and read some codes. Can save you a bunch of time guessing and changing parts

 

[Riperoo]

So, spent a little time digging into this today, battery and alternator seem to be fine, I am pulling 14 volts verified from my EVIC and from my multi meter, and for Sh*ts and giggles I threw the trickle charger on today while I was putzing around the shop today, and when it hit full charge per the trickle charger took it out for a spin, still not working, looked at the EVIC while driving and it says "Auto stop start not ready while battery is charging". So now I am thinking I have a bad Aux battery, which would really blow my mind as its only a year old, so I guess next steps is to pull that out. I can't believe that I am actually chasing a way to make this system work again, only to have to turn it off again!!! OCD is a terrible thing!!!

 

[roaniecowpony]

So, spent a little time digging into this today, battery and alternator seem to be fine, I am pulling 14 volts verified from my EVIC and from my multi meter, and for Sh*ts and giggles I threw the trickle charger on today while I was putzing around the shop today, and when it hit full charge per the trickle charger took it out for a spin, still not working, looked at the EVIC while driving and it says "Auto stop start not ready while battery is charging". So now I am thinking I have a bad Aux battery, which would really blow my mind as its only a year old, so I guess next steps is to pull that out. I can't believe that I am actually chasing a way to make this system work again, only to have to turn it off again!!! OCD is a terrible thing!!!

My issue is starting to look like the regulator in the PCM.

 

[zouch]

i agree with Bob; start with reading the codes.

but i've had a dealer tell me the warranty on the little motorcycle battery is only a year, so don't have too high of an expectation for them.

might be your excuse to do the Aux Batt bypass.

So, spent a little time digging into this today, battery and alternator seem to be fine, I am pulling 14 volts verified from my EVIC and from my multi meter, and for Sh*ts and giggles I threw the trickle charger on today while I was putzing around the shop today, and when it hit full charge per the trickle charger took it out for a spin, still not working, looked at the EVIC while driving and it says "Auto stop start not ready while battery is charging". So now I am thinking I have a bad Aux battery, which would really blow my mind as its only a year old, so I guess next steps is to pull that out. I can't believe that I am actually chasing a way to make this system work again, only to have to turn it off again!!! OCD is a terrible thing!!!

Sponsored