A! Yellow Warning Light Reset

[AZJeepGuy]

Hey everyone,
I had the A! in a circle warning light come on. The last time it was the small battery. I went to O'Reilly and bought a new one. Installed it, and when I started the Jeep and drover around the block the A! error light was gone.
The next day I went out to go to work and the light was on. Bummer. O'Reilly said the could read codes but not reset. I didn't have them read codes because I decided to buy a code reader. I bought a Foxwell NT301 from Amazon.
When it came I read the instructions, connected it and it came back with no codes. I've been driving for the past couple of weeks with no issue.
Today I went back to O'Reilly and had them read the codes. No codes.
What am I missing with my reader? Not sure if anyone has one of these readers but maybe I'm doing something wrong. Two pushes of the ignition. and it connects and reads fine.
How do I reset that warning light?

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[alphawolff]

need a better reader. the warning light always gives codes. check by a dealership

the warning light can illuminate from 100+ dtcs. it isnt always related to the battery. for example a pending (no cel illuminated) misfire will cause the A! to illuminate.

 

[Ratbert]

Note that the two batteries live and die together. If one is bad then it's extremely likely that it took out the other with it. It's a really good idea to replace them in pairs (or nuke the aux).

 

[AZJeepGuy]

need a better reader. the warning light always gives codes. check by a dealership

the warning light can illuminate from 100+ dtcs. it isnt always related to the battery. for example a pending (no cel illuminated) misfire will cause the A! to illuminate.

I was hoping I was just using my code reader wrong. O'Reilly's reader was a cheap one as well.

 

[AZJeepGuy]

Note that the two batteries live and die together. If one is bad then it's extremely likely that it took out the other with it. It's a really good idea to replace them in pairs (or nuke the aux).

Was hoping that isn't the case and wanted to see what the codes were.

 

[AndySpill]

The same auto store that loaned you the code reader likely has a battery load tester that you can borrow.

I would be inclined to use such a tester to load test your batteries independently.

To do this, locate the body ground on the passenger's fender just under the hood. From it a cable will lead to the main battery's negative post.

Leave this cable attached, but temporarily disconnect the other factory cable on the negative post of the main battery, insuring it does not come in contact with body metal.

With this cable disconnected, placing the load tester on the main battery's posts will test only the main battery. Move the negative lead of the load tester on to the end of the loose cable, and even as the positive lead of the load tester remains on the main battery, this will be a test of only the Aux battery.

Independent load testing is important as testing them connected can mask problems as a stronger battery compensates for a weaker one.

If the Aux battery or both batteries are dead you can either replace both the Aux and main batteries, or bypass the Aux. Indicate if you wish instructions on this bypass.

If you replace the main battery consider buying a group H7 size battery. Depending on how you optioned your JL (tow package I think) you may already have an H7 battery there or a slightly smaller H6 size one.

Either will fit, but if the prior one was an H6, once removing this battery you will also need to remove a cleat at the bottom of the battery tray to accommodate the slightly larger H7 battery.

Here is a good place for replacement battery information. https://www.jlwranglerforums.com/forum/threads/main-battery-replacement-talk-jl-jt.100534/

I've had good luck with Odyssey brand batteries but other good brands exist, and any brand can produce its occasional dud. Prices for H6 and H7 batteries are pretty comparable so why not get the slightly beefer battery?

It's most likely that replacing battery/ies here will address your issues. If not, or load testing proves you to have two capable batteries, you might want to bring the vehicle in for service.

At @Ratbert says, please don't replace just one battery if you plan on keeping them both connected.

 

[mwilk012]

Was hoping that isn't the case and wanted to see what the codes were.

Why? Anything else would be more expensive and more complicated. Just replace the battery.

 

[AnebuR]

I suggest bypassing and getting rid of the aux battery altogether for a variety of reasons. There's a huge thread on this forum regarding why you'd want to do that. I'd been driving around without the aux battery for about five years now without incident. Only real downside it that the "A" will always be there if you do that. Small price to pay for the huge increase in reliability.

 

[AndySpill]

Why? Anything else would be more expensive and more complicated. Just replace the battery.

Do I think the batteries the most likely source of the problem here: yes. Statistically that's best bet.

But it's also possible that one or both batteries might be able to accept charge and pass a load test.

It's possible, although not likely, the problem lies elsewhere and replacing the batteries doesn't solve it. Or maybe its both the batteries and something else; again not my first guess

The point is, IMHO, that we test to try to isolate cause to spend the least amount of time and parts cost on addressing issues. Diagnostic codes and independent load testing of the batteries can help rule in and out problems before labor and parts costs are incurred: the only thing more of bummer than these is when they don't solve issues and happen unnecessarily.

 

[AZJeepGuy]

All, thank you for the comments. I already replaced the small battery. I'll go to O'Reilly later and have them load test the main battery expecting that it will be faulty.
Edit: I just saw the Foxwell NT301 has a Plus model for $20 more that has a battery test mode. I still think it should be able to read the codes.

 

[andy29847]

All, thank you for the comments. I already replaced the small battery. I'll go to O'Reilly later and have them load test the main battery expecting that it will be faulty.

Don't be so sure. The parameters of the Jeep start/start system are set to alarm around 12.4v. Under normal guidelines, 12.4v is a good battery.

 

[garyji]

I have the eTorque, but follow this AUX thing pretty close. Referring to Post #8, it is my understanding that if the AUX bypass is done correctly, there will be no lights on the dash??

Keeping up with this because I can't get another eTorque, which I love.

G.

 

[AndySpill]

I have the eTorque, but follow this AUX thing pretty close. Referring to Post #8, it is my understanding that if the AUX bypass is done correctly, there will be no lights on the dash??

Keeping up with this because I can't get another eTorque, which I love.

G.

Here's the skinny on your question.

The dual AGM battery JL, (different of course from your eTorque) performs a pre-crank test on the Aux, or what it thinks is the Aux battery.

The bypass breaks the connection to the Aux battery. If also involves removing Fuse 42, which causes the Power Control Relay (PCR) to be unable to energize, and as a result (when it is energized that is) break the connection between the two factory batteries temporarily to test them separately.

The PCR is a normally closed relay that keeps the batteries in parallel.

As result of these two steps for the bypass, the pre-crank test of the Aux battery now happens, silently, and unknown to any vehicle diagnostics, on all (connected) batteries, of which there is only one connected: your main.

And if it that main battery happens have inadequate voltage it can no less cause the ESS off light to appear in the dash as might be the case under the factory configuration with an aged out Aux battery.

 

[AnebuR]

I have the eTorque, but follow this AUX thing pretty close. Referring to Post #8, it is my understanding that if the AUX bypass is done correctly, there will be no lights on the dash??

Keeping up with this because I can't get another eTorque, which I love.

G.

The opposite. The A will stay displayed. Honestly, I don't even notice it anymore. The whole point of the bypass is increased long-term reliability as well as saving money by no longer needing to replace the aux battery every several years.

 

[mwilk012]

All, thank you for the comments. I already replaced the small battery. I'll go to O'Reilly later and have them load test the main battery expecting that it will be faulty.
Edit: I just saw the Foxwell NT301 has a Plus model for $20 more that has a battery test mode. I still think it should be able to read the codes.

Oreillys is not capable of testing anything. If it’s old, replace it.

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