Throwing All Kinds Of Codes, Errors, then Blackout!

[DanW]

So we are on our way to Moab and my son is driving the JLUR. He first gets a service Stop/Start message, then Service Transmission, then Service Traction Control. We pull off, shut off the Jeep, restart, everything is fine for another hour or two. Then....same stuff, plus he loses power steering! We stop, shut down, restart....gone. The next time it happens, the driver instrumentation cluster goes blank, showing no speed, nothing...only the tach works.

So the first obvious thing is to replace the aux battery, even though it is only 8 months old. The old one tested ok, but I replaced it anyway. We tested the big battery (4 year old Odyssey Pure Lead high performance AGM) and it tests fine. We then drive for about 4 hours with no issues, then he loses everything again, including power steering. We stop, I clear codes and do a reboot with the Tazer, all has been good since, with another 3 hours of driving.

Some of the codes had to do with ABS. I am now suspecting a wheel speed sensor going bad. With a Google search, AI (Gemini) says there is a good chance it is a wheel speed sensor, so we are hitting an O´Reilly in Denver and picking up two for the rear. We will start with the right rear and see how it does.

Any thoughts on this? We did change rear brake pads and the dealer did a checkup and adjustment of the parking brake, so there´s been some rooting around those rear hubs. I´m wondering if that may have jostled the speed sensor on one side and accelerated its failure?

We´re a bit stumped at this point. Oh, btw, the alternator tested just fine. I´m also wondering if the main battery might be causing it, even though it tested ok. It was at 70 something percent, which is ok, but not great.

Any thoughts or similar experiences? This is a 2018 with a manual transmission. Btw, the clutch is performing beautifully, and has been in there for about 6k. I felt the bell housing when it threw the service transmission message and it was not hot and again, there has been no slipping. That is another reason to suspect a rear wheel speed sensor, I believe.

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[VKSheridan]

Dan, I don’t think wheel speed sensors kill power steering or black out your dash.

Dying auxiliary batteries light it up like a Christmas tree but I haven’t heard of them dropping their tantrum with a key cycle.

Turn your steering wheel far left and climb in the R/H wheel well like you’re going to inspect the auxiliary battery. Look to the left on the firewall for a large wire harness connection clipped to the firewall down in that area. Unlatch it, check the pins for moisture and then reconnect it. That connector has been cited as susceptible to poor connection causing intermittent annoyances similar to what you described. Not saying that’s the problem but others have mentioned it affected them and I believe Jeep published a TSB on that critter a few years back.

If that ain’t it, I’d check the CANBUS terminal block under the glove box. That usually throws a ton of random codes and goofy events but it’s usually not self-healing with a key cycle.

Good luck!

 

[Valpo Jeep]

Entirely possible the main battery is your issue. I have always read recommendations on here to replace both the main and aux at the same time. Google says that 70% battery health means its about dead and is likely struggling to provide adequate power to the vehicle.

 

[Stetson]

For sure. Might be a much easier and quicker solution, especially since you are on the road traveling and trying to have some fun

 

[grimmjeeper]

Go through the fuse box. Make sure every fuse and relay is fully seated. They can come from the factory loose, and they can work themselves out over time.

 

[DanW]

Dan, I don’t think wheel speed sensors kill power steering or black out your dash.

Dying auxiliary batteries light it up like a Christmas tree but I haven’t heard of them dropping their tantrum with a key cycle.

Turn your steering wheel far left and climb in the R/H wheel well like you’re going to inspect the auxiliary battery. Look to the left on the firewall for a large wire harness connection clipped to the firewall down in that area. Unlatch it, check the pins for moisture and then reconnect it. That connector has been cited as susceptible to poor connection causing intermittent annoyances similar to what you described. Not saying that’s the problem but others have mentioned it affected them and I believe Jeep published a TSB on that critter a few years back.

If that ain’t it, I’d check the CANBUS terminal block under the glove box. That usually throws a ton of random codes and goofy events but it’s usually not self-healing with a key cycle.

Good luck!

Is it this?

8

 

[DanW]

Battery is next, but we're trying to get the connector under the aux battery undone. The lock tab on the connector was brittle and broken. We're going to check it and hit it with WD-40.

 

[VKSheridan]

The one spelled out in the TSB has a flip latch and was a large (28 pin or so) connector.

 

[DanW]

The one spelled out in the TSB has a flip latch and was a large (28 pin or so) connector.

Pins looked perfect. Hit it with WD-40. NEW Walmart Platinum Plus is now in.

 

[tk1700]

I had similar lights on a 2019 JLUS. It was the CANBUS, located behind the glove box..

 

[DanW]

Update: I checked the connections behind the glove box and they were all good. Fuse box was good....I had checked it when replacing the Aux battery.

Anyway, I think the big deal was the battery. We made the last 4.5 hours of the drive with zero issues. That´s a good sign.

We are hitting our first trails around Moab tomorrow, so we will see how she does with a long day of wheeling.

Thank you all for the suggestions! I will update again probably tomorrow evening.
This JLUR is one of the early ones. It has 106k miles and has really given me no trouble. It´s on it´s 4th trip to Moab. Hopefully, the trouble is behind us and it will perform as it always has.

 

[HHGadget]

Update: I checked the connections behind the glove box and they were all good. Fuse box was good....I had checked it when replacing the Aux battery.

Anyway, I think the big deal was the battery. We made the last 4.5 hours of the drive with zero issues. That´s a good sign.

We are hitting our first trails around Moab tomorrow, so we will see how she does with a long day of wheeling.

Thank you all for the suggestions! I will update again probably tomorrow evening.
This JLUR is one of the early ones. It has 106k miles and has really given me no trouble. It´s on it´s 4th trip to Moab. Hopefully, the trouble is behind us and it will perform as it always has.

FWIW my ‘18 JLUR had random intermittent dash / electrical freakouts.
Shifter would show rowing through the gears (when it wasnt), power steering loss, windshield wipers on, etc etc.
Then it would go away on a restart, then come back a week, or a month or 3 months later.
Connections appeared fine on the canbus block under the glove box.
Finally ordered one and swapped it out.
First time in years the jeep was reliable and trustworthy.
Haven’t had a problem in years now since replacing it.
Never could figure out why the very random nature of it’s failure.

 

[DanW]

FWIW my ‘18 JLUR had random intermittent dash / electrical freakouts.
Shifter would show rowing through the gears (when it wasnt), power steering loss, windshield wipers on, etc etc.
Then it would go away on a restart, then come back a week, or a month or 3 months later.
Connections appeared fine on the canbus block under the glove box.
Finally ordered one and swapped it out.
First time in years the jeep was reliable and trustworthy.
Haven’t had a problem in years now since replacing it.
Never could figure out why the very random nature of it’s failure.

So you ordered a new Canbus or Canbus block?

If it comes back, that´s probably going to be next.

 

[HHGadget]

So you ordered a new Canbus or Canbus block?

If it comes back, that´s probably going to be next.

Yes I ordered the block.
I would have never known about it if it wasn't for this forum. The dealership couldn’t figure it out as i could never get the car to have the issue when it was at the dealer.

 

[DanW]

Yes I ordered the block.
I would have never known about it if it wasn't for this forum. The dealership couldn’t figure it out as i could never get the car to have the issue when it was at the dealer.

How much was that part and was it pretty easy to install?

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