Rear axle locker glitch leads to unrelated codes?

[Chaos Theory]

So I've had this Jeep for about a month, and I took it to a local ORV park to do some tests on systems I haven't used much yet...

I switch between 4H and 4L a couple times. I then wanted to test the rear locker (Mojave) in 4H. I hold down the traction control for the 5 seconds until it beeps, then am able to lock the rear. I then get a code "Service antilock brakes". I drive for a minute or two, low speed on gravel, then try to unlock the locker. It tries for about a minute then just stops without unlocking. I then get a "service axle locker" or something similar, along with "brake warning light".

I shut the car down and turn it back on. The locker again thinks about it for about 30 seconds and finally unlocks. I go through this process a few more times (locker on/off) without issue, and everything happens within the usual 5 or so seconds. Not sure if something was stuck, lubricant had to work its way in there, or whatever... Eventually I'm back in 2H and no dash lights during the drive home.

Are these random glitches common? Should I just clear the codes with my Taser and hope it doesn't happen again?

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[SamJ3]

I had a simpler but similar situation in my 2022 Gladiator Sport. When wheeling up a very rocky forest road in 4-low last month, the brake warning light lit up. I checked the park brake handle - not that. Brakes felt fine, but still, a warning. Turned off the vehicle, then restarted - and that seemed to clear the error.

Also, later I got a Uconnect notice that the brakes needed to be serviced, though that too cleared and now shows normal.

My experience says problems that randomly go away eventually randomly return.

Has anyone else seen this or have a plausible explanation?

 

[Pescatoral Pursuit]

My lockers don't want to unlock after being engaged beyond a couple minutes. I have to play the game of turning the truck off, waiting a minute or two, then driving again and it will usually disconnect within ¼ mi after that.

A friend who's been in the industry for a while says that's normal.

 

[Maximus Gladius]

Not normal. If this was mine I’d take off the diff cover (gasket is reusable)unplug the locker sensor, undo the single Torx screw holding it in, then gently lift the sensor off the magnet. Inspect it, maybe pull off any magnetic debris stuck to it. Spray out the diff with brake cleaner and reinstall it all back.

It would also be a good time to see if the locker sensor has any diff fluid in it. Warranty replace it.

 

[Pescatoral Pursuit]

Not normal. If this was mine I’d take off the diff cover (gasket is reusable)unplug the locker sensor, undo the single Torx screw holding it in, then gently lift the sensor off the magnet. Inspect it, maybe pull off any magnetic debris stuck to it. Spray out the diff with brake cleaner and reinstall it all back.

It would also be a good time to see if the locker sensor has any diff fluid in it. Warranty replace it.

Was this causing the same symptoms in your diff and did this fix it?

I also have excessive play in the driveline and thinking it's premature failure in the differential, and also may corroborate metal particle contamination.

 

[Maximus Gladius]

Was this causing the same symptoms in your diff and did this fix it?

I also have excessive play in the driveline and thinking it's premature failure in the differential, and also may corroborate metal particle contamination.

I don’t have excessive play but what I did have was a long delay in locker engagement and disengagement. At times the dash light for the lockers would blink so long it would quit and I’d have to try again.

After I cleaned the locker sensor magnet, engagement and disengagement happened on the 3rd blink of the dash light.

 

[Pescatoral Pursuit]

Sweet. Lockers that engage and disengage when you want them to must be a beautiful thing.

 

[Maximus Gladius]

Sweet. Lockers that engage and disengage when you want them to must be a beautiful thing.

Absolutely! I also “potted” my locker sensors so I would never have to deal with oil getting inside them.

 

[Maximus Gladius]

Your sensor magnet most likely has some good magnetic debris clogging it up. Does your diff have a drain plug? My 21 JTR does and when I pulled that some time ago the drain plug magnet had a good mound of stuff on it. That would tell you the locker sensor magnet would at least have the same thing.

 

[jac04]

I also have excessive play in the driveline and thinking it's premature failure in the differential, and also may corroborate metal particle contamination.

If you look at the way the factory Tru-Lok ELD is made, it is my understanding that the spider gears & side gears are made with a significant amount of play (backlash) to allow for quicker/easier engagement of the dog clutch teeth when you select the 'lock' function. There is also quite a bit of play between the 4 legs of the outboard dog clutch and the diff carrier.

So, the 'excessive play' may just be a combination of the normal play of the spider & side gears as well as the 4 legs of the dog clutch and the differential carrier.

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