Start stop not working

[Wynfuller]

So I live in Cleveland Oh & I got a 2020 Gladiator Rubicon an I just got it undercoated with fluid film & my start stop does not work now has this happened to anybody else? Should I take it to the dealer?

There is a pcm recall that may fix the issue. I had the same issue a while back. Wasn’t batteries, high amp fuses, pcr. Thanks to Mr. Bill. He’s a big help

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[Mr._Bill]

I am experiencing the same thing as @Wynfuller as of today. Both batteries tested good shut off (I pulled the aux so it wasn't going to be exactly the same as main). No issues with starting. Running voltage is 14.5+. 2.5yr old OEM batteries. No CEL, no battery warning. Just a message on the dash that the start stop is unavailable with the circle arrow A and !.

Where are N1, N2, and N3 physically located? I am just starting to digest the schematic posted above and have not messed with the electrical system in this vehicle at all. The whole aux battery concept is new to me.

The N posts are on the side of the fuse box.

The error message you are seeing indicates the Aux Battery failed the startup test. The system voltage at 14.5+ shows it is trying to charge the batteries.

Charge each battery, then let them sit overnight with no load. Measure the voltage on each one. It should be in the neighborhood of 12.8 if the battery is in good shape. Anything below 12.3 means you should start shopping for new batteries.

The average life expectancy of batteries in the JT is about three years. Some go longer, some die sooner. The truck has a high parasitic draw. To get the longest life out of the batteries, it needs driven several times a week for at least thirty minutes, or needs to have a battery maintainer connected when parked.

The primary purpose of the Aux Battery is to keep the computers and electronics stable during ESS events. The two batteries are paralleled together all the time, except during the startup test and during ESS events.

When one of the batteries starts to fail, it can become a drain on the other. Based on your symptoms, I would suggest replacing both batteries soon. You can play dealer roulette, if you're still in warranty, and try to get them to replace the batteries. They will charge them, put them on the tester, send the results to Jeep, and wait for a decision.

My suggestion would be to purchase a ACDelco 94R and Aux14 from Amazon and save yourself a lot of time and hassle.

 

[MikeInMo]

The N posts are on the side of the fuse box.

The error message you are seeing indicates the Aux Battery failed the startup test. The system voltage at 14.5+ shows it is trying to charge the batteries.

Charge each battery, then let them sit overnight with no load. Measure the voltage on each one. It should be in the neighborhood of 12.8 if the battery is in good shape. Anything below 12.3 means you should start shopping for new batteries.

The average life expectancy of batteries in the JT is about three years. Some go longer, some die sooner. The truck has a high parasitic draw. To get the longest life out of the batteries, it needs driven several times a week for at least thirty minutes, or needs to have a battery maintainer connected when parked.

The primary purpose of the Aux Battery is to keep the computers and electronics stable during ESS events. The two batteries are paralleled together all the time, except during the startup test and during ESS events.

When one of the batteries starts to fail, it can become a drain on the other. Based on your symptoms, I would suggest replacing both batteries soon. You can play dealer roulette, if you're still in warranty, and try to get them to replace the batteries. They will charge them, put them on the tester, send the results to Jeep, and wait for a decision.

My suggestion would be to purchase a ACDelco 94R and Aux14 from Amazon and save yourself a lot of time and hassle.

Thanks. I will check tomorrow morning to see what I get. I'm already gone for the day.

I do drive about 35min twice a day most weeks. Last week I happened to drive my wife's car to save some mileage while she was out of town and drove the Gladiator for the first time in several days yesterday when this happened. The age and short term change in driving pattern fit what you are saying about catching batteries as they are starting to fail.

 

[Lost1wing]

I am experiencing the same thing as @Wynfuller as of today. Both batteries tested good shut off (I pulled the aux so it wasn't going to be exactly the same as main). No issues with starting. Running voltage is 14.5+. 2.5yr old OEM batteries. No CEL, no battery warning. Just a message on the dash that the start stop is unavailable with the circle arrow A and !.

Where are N1, N2, and N3 physically located? I am just starting to digest the schematic posted above and have not messed with the electrical system in this vehicle at all. The whole aux battery concept is new to me.

You did remove the f42 fuse when you pulled the aux? I'm curious because you would have noticed the N1, N2 and N3 terminals under the fuse panel cover.

 

[MikeInMo]

You did remove the f42 fuse when you pulled the aux? I'm curious because you would have noticed the N1, N2 and N3 terminals under the fuse panel cover.

I did not

 

[Lost1wing]

I am not a fan of doing the Aux delete. I took your statement of "pulled the Aux" meaning the Aux is out of the sytem. Removing f42 would prevent the pcr from doing it's start up test. If you did remove the aux without removing f42 fuse, you can expect a fault.

 

[sharpsicle]

I am not a fan of doing the Aux delete. I took your statement of "pulled the Aux" meaning the Aux is out of the sytem. Removing f42 would prevent the pcr from doing it's start up test. If you did remove the aux without removing f42 fuse, you can expect a fault.

I don't think he's saying he deleted the aux from the system. Just that he disconnected it during his voltage tests to ensure he was getting accurate readings.

 

[Lost1wing]

I don't think he's saying he deleted the aux from the system. Just that he disconnected it during his voltage tests to ensure he was getting accurate readings.

I kind of got that impression after reading it again.

 

[Lost1wing]

If he was to pull f42 and his fault goes away, the Aux is the issue. That would explain 14.5v all of time with the engine e running.

 

[MikeInMo]

I just pulled the aux battery assuming it was bad/going bad and needed to be replaced. I was not doing a delete.

It tested 12.74V on the bench about 30 min after I got home, so I put it back and ended up posting here asking about it.

I forgot to check the voltage this morning after it sat overnight.

 

[Mr._Bill]

I just pulled the aux battery assuming it was bad/going bad and needed to be replaced. I was not doing a delete.

It tested 12.74V on the bench about 30 min after I got home, so I put it back and ended up posting here asking about it.

I forgot to check the voltage this morning after it sat overnight.

That shows it is close to fully charged. Let it sit a few hours, overnight if possible, with no load and then check again. If it hasn't changed, or drops very little, the battery should be good.

 

[Lost1wing]

If your aux and main are both good, I would go back and check the fuse array before putting it back together. Maybe you accidentally shorted one of your cables and that is why you are getting your fault.

 

[MikeInMo]

That shows it is close to fully charged. Let it sit a few hours, overnight if possible, with no load and then check again. If it hasn't changed, or drops very little, the battery should be good.

I finally had a chance to mess around with it this morning (Saturday). It sat overnight without running before checking this morning.

With my meter neutral on the ground connection on the body between the main battery and PDC, all posts N1-N7 were 12.59V.

I pulled fuse F42, started it, and ran for about 30 or so seconds. No error.

I replaced fuse F42 and started it. No error. Did I reset something or get enough of a charge on the first start to pass the start up test? The fuse was fully seated when I pulled it.

Another data point....Thursday morning was cold. I remote started to warm it up. When I got in and hit the ignition a few minutes later, no error. I assumed it charged enough while warming up to pass the start up test. Friday morning the error was back on a regular cold start.

 

[Mr._Bill]

I finally had a chance to mess around with it this morning (Saturday). It sat overnight without running before checking this morning.

With my meter neutral on the ground connection on the body between the main battery and PDC, all posts N1-N7 were 12.59V.

I pulled fuse F42, started it, and ran for about 30 or so seconds. No error.

I replaced fuse F42 and started it. No error. Did I reset something or get enough of a charge on the first start to pass the start up test? The fuse was fully seated when I pulled it.

Another data point....Thursday morning was cold. I remote started to warm it up. When I got in and hit the ignition a few minutes later, no error. I assumed it charged enough while warming up to pass the start up test. Friday morning the error was back on a regular cold start.

The cold weather will make it drop faster, and take longer to charge. 12.6v is marginal, fully charged is 12.8v or higher. I would suggest a battery maintainer if you are not driving it every day.

 

[MikeInMo]

The cold weather will make it drop faster, and take longer to charge. 12.6v is marginal, fully charged is 12.8v or higher. I would suggest a battery maintainer if you are not driving it every day.

Removing and replacing the F42 fuse seems to have reset something. I haven't had the warning message since then, and the start/stop operated while I was in line at the bank. Temps are similar to last week.

I'm going to keep an eye on it.

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