Service 4wd in 2wd?

[j.o.y.ride]

Had the Service 4wd light come on 2 separate trips while driving around town yesterday. It has happened once or twice in the past, always in 2wd, and always gone away. But never been twice in a half hour.

Overland model so it isn't the lockers melting down.

FAD? Not making any noise
Sensor of some sort? Seems plausible.
Other ideas?

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[jac04]

Mine recently came on in 2WD and has been on steady for the past 500 miles. My JT has 11500 miles on it. Some quick searching leads me to think it could be the FAD Actuator, Transfer Case Position Switch or 4WD control unit.

I can change into 4H Auto (I have Selec-Trac), 4H Part-Time and 4L, and the dash cluster indicates it is in whatever mode I select. However, 4WD is definitely not engaging. Also, I can get under the Jeep in any of these modes and turn the front driveshaft by hand. This means that the FAD is not connected and the transfer case has not engaged the front driveshaft.

I have an appointment for next week. Hopefully with the light on all the time they can plug in and it will tell them axactly what is wrong.

 

[j.o.y.ride]

Yeah I am taking mine in Monday, planned to take it off road day after turkey day. Wondering what it may be and if would be readily fixed or bigger issue with parts needed.

I wouldnt have that issue of not engaging 4wd, I have the standard tcase. It's in it or it isn't.

 

[jac04]

Any update?

 

[j.o.y.ride]

Any update?

I wasnt actually able to get it in, but the light comes on almost every time now. I should be going in next week.

 

[P90Ed]

Any update? I'm having the same issue. Second time. First time they replaced a speed sensor.

 

[jac04]

Any update? I'm having the same issue. Second time. First time they replaced a speed sensor.

What code did they find on yours when you brought it in and they replaced the speed sensor?

On mine, they found DTC C140A-11, but the tech failed to properly follow all the diagnostic steps. So, they erroneously replaced the control module, but the final fix was a new shift motor. Here's the whole story:
https://www.jeepgladiatorforum.com/forum/threads/serv-4wd-dealership-is-stumped.65334/

 

[j.o.y.ride]

been significantly lazy on this, i havent driven much in the past 2 months so haven't bothered

 

[Jclow801]

I've had the same problem on two separate occasions (which ended up being two separate problems) Initially it was the FAD Actuator itself, it was making intermittent noise.. Then the second time it was the wires that led to the FAD.. Again making noise. They replaced the actuator under warranty and fixed the wires under warranty as well. Only concern now is what damaged driving with it the SERV 4WD light on caused. I expressed this concern to my dealer as it was obvious that they hadn't inspected my axle to ensure that no damage had been caused, and they advised me that if I change my differential fluid & it seems like there's any metal flake or anything wrong to keep the fluid, take a picture, and bring it to them. 2020 JT Sport S w/ 15k miles.

I am guessing w/ it making noise.. It was causing damage. My reading leads me to believe that if the FAD isn't getting proper signals from the computer it should just stay in the open position, leaving you in 2WD all the time, no matter what the transfer case is set to, but I could always use 4WD so I am thinking damage was caused. New axle under warranty? I probably need to change that fluid soon.

 

[P90Ed]

What code did they find on yours when you brought it in and they replaced the speed sensor?

On mine, they found DTC C140A-11, but the tech failed to properly follow all the diagnostic steps. So, they erroneously replaced the control module, but the final fix was a new shift motor. Here's the whole story:
https://www.jeepgladiatorforum.com/forum/threads/serv-4wd-dealership-is-stumped.65334/

I conveniently got no paperwork when I picked up my truck from the repair so no idea what the code was. As I said though - with my Tazer Mini Lite there were no codes to clear...

 

[j.o.y.ride]

Finally got un-lazy and took it in. Scanned as a transfer case sensor which they have seen a lot of.

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