Two weeks and 470 miles of Jeep ownership and already a Check Engine Light

[DanJT]

Must have been a bad batch... Maybe. glad it's running great now!

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[OldButStillJeeping]

I did not read the whole thread, but I hate seeing posts like this. It's not a Jeep thing, its an every new vehicles thing. Rolling computers made by happy, or, disgruntled employees. Or simply a bad electronic component(s) that somehow passed Quality Control testing.

Knock on wood, but my bought new in 2021, JT Mojave has been flawless for almost 67K miles now. But when the Aux battery died a few months ago it took the main battery with it and caused some crazy dash issues. Replaced both batteries, and she is back to perfect.

The problem with high technology is the price and time to diagnos and fix it.

Be well. Jeep on.

Eric

 

[DanJT]

I did not read the whole thread, but I hate seeing posts like this. It's not a Jeep thing, its an every new vehicles thing. Rolling computers made by happy, or, disgruntled employees. Or simply a bad electronic component(s) that somehow passed Quality Control testing.

Knock on wood, but my bought new in 2021, JT Mojave has been flawless for almost 67K miles now. But when the Aux battery died a few months ago it took the main battery with it and caused some crazy dash issues. Replaced both batteries, and she is back to perfect.

The problem with high technology is the price and time to diagnos and fix it.

Be well. Jeep on.

Eric

What were the dash issues? Mine out of the blue lit up the Start/Stop issue light, the traction control issue, and the ABS light. I'm attempting a trickle charge before forking out the money for ne batteries.

 

[Splenda]

What were the dash issues? Mine out of the blue lit up the Start/Stop issue light, the traction control issue, and the ABS light. I'm attempting a trickle charge before forking out the money for ne batteries.

Battery needed to be charged. I guess it ran low while it was sitting on the lot. I charged the battery, and none of those issues ever came back.

 

[DanJT]

Battery needed to be charged. I guess it ran low while it was sitting on the lot. I charged the battery, and none of those issues ever came back.

That's what I am doing, fingers crossed.

 

[ShadowsPapa]

But when the Aux battery died a few months ago it took the main battery with it and caused some crazy dash issues. Replaced both batteries, and she is back to perfect.

Yeah, people always want to say "aux battery went and took out the main" when in reality, it can be the other way around, and actually has happened that way just as often.
Many here have had the main battery go - and they got another year on the aux battery.
Normally, unless a battery shorts when it goes, it will have no impact on the other in the pair or array.

Low voltage causes the "crazy dash issues" - regardless of the battery, since they run in parallel 99.999999% of the time. They are always connected to each other as a pair except at the initiation of a starter engagement.

The parasitic draw of modern vehicles, and the shorter drives many of these get is a major issue behind the battery problems we see.

Hardly anyone drives far/long enough to get a battery back up to 100% before they get to work and shut it off.

 

[ShadowsPapa]

What were the dash issues? Mine out of the blue lit up the Start/Stop issue light, the traction control issue, and the ABS light. I'm attempting a trickle charge before forking out the money for ne batteries.

Separate the batteries, charge each one separately and reset the IBS.
Charging each battery on its own gives you a chance to observe the battery health - how does it go charging, when the charger is disconnected to do the other battery, does the first one charged keep the charge or drop off quickly, that sort of thing.
You can tell a lot by using a good AGM charger (not trickle charge) on each battery.

 

[DanJT]

Thanks PS, Ill try that tomorrow. I disconnected the aux ground and trickled it to 100% but still has the lights. I'll start over and follow your advice, thanks again.

 

[DanJT]

OK, just read over several threads on this subject. And.... I screwed the pooch on this. While charging the aux (I think) I did not disconnect the IBS from the negative post, nor did I disconnect the aux positive from the post. So as stated before tomorrow I'm going to fall back and punt.. (start over)
Man, this electrical system is something else!

 

[ShadowsPapa]

Man, this electrical system is something else!

Yup - no one's going to argue about that!

 

[NC_Overland]

Yes

You sure about that? Mine didn’t.

Long story short, I changed the aux battery and not the main battery because it tested fine. Shortly thereafter my main battery died and my jeep did weird stuff and wouldn’t power off and drained the aux battery. Even after I disconnected the main battery. I put in a new battery and charged it and reset the IBS and I was still getting no aux switches, no auto start stop, etc. I had to pull the aux battery out and charge it and all my issues went away.

 

[NC_Overland]

OK, just read over several threads on this subject. And.... I screwed the pooch on this. While charging the aux (I think) I did not disconnect the IBS from the negative post, nor did I disconnect the aux positive from the post. So as stated before tomorrow I'm going to fall back and punt.. (start over)
Man, this electrical system is something else!

Have you lost all your apps yet? When I replaced my aux battery and reset everything the first time, I lost all my apps and a lot of vehicle controls like climate control, heated seats, etc. It all came back over the next few days.

 

[ShadowsPapa]

You sure about that? Mine didn’t.

Long story short, I changed the aux battery and not the main battery because it tested fine. Shortly thereafter my main battery died and my jeep did weird stuff and wouldn’t power off and drained the aux battery. Even. After I disconnected the main battery. I put ina. New battery and charged it and reset tv IBS and was still getting no aux switches, no auto start stop, etc. I had to pull the aux battery out and charge it and all my issues went away.

Different capacities can lead to uneven charging, especially if one is weaker than the other. A good AGM charger goes through multiple (4, I believe) phases of charging. If one battery isn't up to snuff, it might not work out well.

Ideally, both would charge together fine. But - that's assuming both batteries are in similar state of health.

 

[DanJT]

Have you lost all your apps yet? When I replaced my aux battery and reset everything the first time, I lost all my apps and a lot of vehicle controls like climate control, heated seats, etc. It all came back over the next few days.

Not yet, but thanks for the heads up because that would have shorted out my fuse. Lol

 

[NC_Overland]

Different capacities can lead to uneven charging, especially if one is weaker than the other. A good AGM charger goes through multiple (4, I believe) phases of charging. If one battery isn't up to snuff, it might not work out well.

Ideally, both would charge together fine. But - that's assuming both batteries are in similar state of health.

Both were brand new, one was drained and one was fully charged. I charged the main battery after installing to make my jeep stop freaking out, but charged it before driving.

It was weird it kept trying to start and I couldn’t turn it off or turn the lights off.

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