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'A' - with yellow circle arrow around it (dash light)

Cleoncini

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Just got the lovely A! light yesterday. Tazer confirmed the code was P00FD. Unmarried and removed the Tazer. JL goes into the dealer tomorrow morning. Odd for this to pop up at a tick under 11K miles?
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Jeepet76

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Hereā€™s the latest on my ā€˜21 Rubicon JL with the Start/Stop issue: I drove my Jeep over the weekend and never receive a warning message; however, I know it didnā€™t repair itself so I took it by the Jeep service department this morning. They ran another diagnostic test and told me that I needed to replace the radio frequency hub (RFH). Huh?

They said this is the last step before replacing the powertrain control module. The problem now is the part number for the RFH is not listed by Chrysler since this is a 2021 model. I guess Iā€™m confused on how the radio frequency hub is connected to the Start/Stop system. Any guesses?
So I don't know alot about the mechanics part and I can't imagine a radio would fix the problem. I can however tell you that I have a JL 2020 and recently had my radio upgraded from an outside vendor. The dealership themselves told me they wouldn't do it. Ever since I changed my radio the auto stop start function doesn't work on my jeep. It somehow has been over rided and I no longer have to push that button to turn it off every time I start her. The audio shop also told me that everything was connected through the radio... radio kinda of being the mother board or brain of the jeep. Like I said, I don't know much about it but it does make some sense. Fortunately I haven't had this yellow A light come on but my friend has a JL 2021 with this problem which is why I'm here looking for answers for her. Good luck to you all!
 

Htfan

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So I don't know alot about the mechanics part and I can't imagine a radio would fix the problem. I can however tell you that I have a JL 2020 and recently had my radio upgraded from an outside vendor. The dealership themselves told me they wouldn't do it. Ever since I changed my radio the auto stop start function doesn't work on my jeep. It somehow has been over rided and I no longer have to push that button to turn it off every time I start her. The audio shop also told me that everything was connected through the radio... radio kinda of being the mother board or brain of the jeep. Like I said, I don't know much about it but it does make some sense. Fortunately I haven't had this yellow A light come on but my friend has a JL 2021 with this problem which is why I'm here looking for answers for her. Good luck to you all!
From your description, I would assume that one or both of your batteries is too low for ESS to engage. I would also guess you'll see a status on your dash start/stop screen saying battery not ready charging.

Your aftermarket headunit install probably drained the battery quite a bit without the engine running.

I would check your battery voltage and put a battery charger on it overnight.
 

Jeepeto

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I had this issue after calibrating for 35ā€ tires on a 6MT. Something to do with the final drive ratio being outside of acceptable parameters and for whatever reason that triggers the ā€œa-holeā€ light. The dealership reflashed the ECU and it fixed the issue. I doubt thatā€™s the issue if it showed up after you just changed your radio, but on the off chance that your in a 6MT with oversized tires and youā€™re all out of ideas it might be something to look at.
 

Jeepet76

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From your description, I would assume that one or both of your batteries is too low for ESS to engage. I would also guess you'll see a status on your dash start/stop screen saying battery not ready charging.

Your aftermarket headunit install probably drained the battery quite a bit without the engine running.

I would check your battery voltage and put a battery charger on it overnight.
I don't seem to have any problems with the battery ... yet... and no signs of issues.... however I do hear a clicking from the radio even when car is off. Besides the clicking noise everything works great. Guessing I should probably get it looked at though... just in case. Thank you for your help.!
 

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Htfan

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I don't seem to have any problems with the battery ... yet... and no signs of issues.... however I do hear a clicking from the radio even when car is off. Besides the clicking noise everything works great. Guessing I should probably get it looked at though... just in case. Thank you for your help.!
No problems yet...

Did you get a chance to look at the start /stop status on your dash menu? Or check your battery voltage?
 

Jeepet76

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No problems yet...

Did you get a chance to look at the start /stop status on your dash menu? Or check your battery voltage?
I personally don't have a problem with my start/stop. My after market radio has seemed to turn that off. (My neighbor has a 2021 and she is having the that problem (all factory parts)). And I have not checked the battery as of yet, not really sure the easiest way for me to do that. My dash doesn't say anything is wrong. We looked through her dash, everything was fine, but she did say when the start/stop light came on (2ce now) that the dash said unavailable. She has an appt on the 7th. I do want to thank you for being kind and not judging... the forums on fb... there's always the nasty bunch that like to belittle people instead of being kind and helping. šŸ˜
 

Htfan

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I personally don't have a problem with my start/stop. My after market radio has seemed to turn that off. (My neighbor has a 2021 and she is having the that problem (all factory parts)). And I have not checked the battery as of yet, not really sure the easiest way for me to do that. My dash doesn't say anything is wrong. We looked through her dash, everything was fine, but she did say when the start/stop light came on (2ce now) that the dash said unavailable. She has an appt on the 7th. I do want to thank you for being kind and not judging... the forums on fb... there's always the nasty bunch that like to belittle people instead of being kind and helping. šŸ˜
Just trying to help. Realize we all have different knowledge levels and ability.

The reason I'm concerned is what you've described "can" be an indication of a battery on it's way out. So it would be good to verify things are OK before being stranded somewhere with a dead battery.
 

dog0311

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This started up after having my head unit replaced under warranty. I believe it is associated with the auto stop/start function. It goes away after shut off, then starts back up a few minutes after driving.

I have the mini tazer. Can it permanently shut this off? I cleared when it popped up once, but after shutting off and turning back on it popped up again. To be fair, it was a quick attempt on my end.

How do I permanently make go away? Dealership best option?
The 21 Gladiator has a switch on the dash to turn it off.
 
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I do have a 6MT w 37" tires. The tazer website says there is a process you need to go through - resetting, driving in top gear over 45mph for over 60 seconds or something like that. Didn't work. Others set you need to reset the ESS battery by unplugging it from where it is wired by the frame. Didn't work. Took it to dealership, they tried a bunch of stuff - testing charge on battery, etc. - didn't work.

At this point I've just lived with it for almost a year......
 

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Slgraha1974

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I've had a '21 Rubicon for less than 3 months. Last week, the Auto Start/Stop warning light came on after putting my doors back on. Unplugged and plugged all the doors, the light went off but came back on the next day. Unplugged and plugged the doors but this time the light stayed on. This passed weekend, we took the doors off again and after putting them back on, no warning light so far. However, I noticed last week while this light was on, the only door that unlocks after turning off the vehicle is the driver. Last night, my husband was with me and when he opened the passenger door, we heard all doors unlock. Last week, I was using the key fob to unlock the driver back door, so this morning I tried to unlock all the doors using the unlock button on the driver side door. Nothing, it did nothing. I had to use the key fob again. I know I need to take it to the shop, which I hate, but my question is could this all be related to the ESS system/aux battery?
 

Rhinebeck01

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I've had a '21 Rubicon for less than 3 months. Last week, the Auto Start/Stop warning light came on after putting my doors back on. Unplugged and plugged all the doors, the light went off but came back on the next day. Unplugged and plugged the doors but this time the light stayed on. This passed weekend, we took the doors off again and after putting them back on, no warning light so far. However, I noticed last week while this light was on, the only door that unlocks after turning off the vehicle is the driver. Last night, my husband was with me and when he opened the passenger door, we heard all doors unlock. Last week, I was using the key fob to unlock the driver back door, so this morning I tried to unlock all the doors using the unlock button on the driver side door. Nothing, it did nothing. I had to use the key fob again. I know I need to take it to the shop, which I hate, but my question is could this all be related to the ESS system/aux battery?
@Slgraha1974

No,it is not related to your battery(s)

Your issue is undoubtedly directly related to bent pins on your door harness(s).

Try to remedy this pin issue yourself of have dealer do...

.
 

Slgraha1974

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@Slgraha1974

No,it is not related to your battery(s)

Your issue is undoubtedly directly related to bent pins on your door harness(s).

Try to remedy this pin issue yourself of have dealer do...

.

Thank you! I've tried looking at the pins when the warning light was on. Didn't see any that looked bent but anything is possible. I plan to call the dealership this morning to have it looked at but I hate having to take it in. It's already been in the shop once the 1st week I got it because the horn kept randomly going off.
 

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Thank you! I've tried looking at the pins when the warning light was on. Didn't see any that looked bent but anything is possible. I plan to call the dealership this morning to have it looked at but I hate having to take it in. It's already been in the shop once the 1st week I got it because the horn kept randomly going off.
@Slgraha1974

Lots here have had the issue you are having.... You have to be very very careful with those door harnesses.
 

Fatboy97

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This started up after having my head unit replaced under warranty. I believe it is associated with the auto stop/start function. It goes away after shut off, then starts back up a few minutes after driving.

I have the mini tazer. Can it permanently shut this off? I cleared when it popped up once, but after shutting off and turning back on it popped up again. To be fair, it was a quick attempt on my end.

How do I permanently make go away? Dealership best option?
I had the same problem and the dealer insisted it was a problem with the small battery. I disconnected the main battery both positive and negative terminals for about 15 minutes. I also tested both batteries individually and found the main battery would not charge over 65%. The small battery checked out perfect. When I reconnected the battery terminals the code cleared. I also purchased a new main battery (Jeep dealership would not warranty). From what I understand most of the time it is a issue with the smaller battery but you should check both batteries by disconnecting them both from each other and checking them on their own. Iā€™m a little baffled as the code is for the auto start stop which I believe is tied to the smaller battery however in the end my problem is solved. This repair on my Jeep was not performed by any dealership. When the smaller battery needs replacing I will be bypassing it and will run with one battery as all previously owned vehicles have done. No auto start stop here.
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