"4WD SERV" warning light override

[Roky]

Did you simply re-route the factory wiring or did you buy two new wiring harnesses so the stock switches could be reactivated if necessary?

I ran the Mopar wiring harnesses to the diffs and I just plug them in when we’re headed out. There’s a little chassis symbol with an exclamation point beside it that stays on the dash over the fuel gauge. Also there’s a service locker message at start up but goes away like the seatbelt sign. This is because you’re bypassing the computer.

The Mopar harness is just hot and ground. If it’s going to be a while between wheeling I’ll plug factory harness back in so the wife doesn’t have to look at the dash code.

I did this back before the tazer was able to engage lockers. And I wanted to use my lockers in 4 hi and the rear in 2 wd. Even though I can use the tazer now to do it , mine takes a little longer to disengage and aux switches are instantaneous. Here’s my thread on it from back in the day, lol.

https://www.jlwranglerforums.com/forum/threads/lockers-whenever-i-want-them.18939/post-460016

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[limeade]

I ran the Mopar wiring harnesses to the diffs and I just plug them in when we’re headed out. There’s a little chassis symbol with an exclamation point beside it that stays on the dash over the fuel gauge. Also there’s a service locker message at start up but goes away like the seatbelt sign. This is because you’re bypassing the computer.

The Mopar harness is just hot and ground. If it’s going to be a while between wheeling I’ll plug factory harness back in so the wife doesn’t have to look at the dash code.

I did this back before the tazer was able to engage lockers. And I wanted to use my lockers in 4 hi and the rear in 2 wd. Even though I can use the tazer now to do it , mine takes a little longer to disengage and aux switches are instantaneous. Here’s my thread on it from back in the day, lol.

https://www.jlwranglerforums.com/forum/threads/lockers-whenever-i-want-them.18939/post-460016

Thanks, good info!

 

[Roky]

Thanks, good info!

Sure, no problem

 

[Geronimo]

I’m still using the fad....... But the best way in my opinion, is to replace the 2 piece axle with a one piece axle like the rcv........

You can see the indentation on the axle shaft in the picture, that’s where the fork of the fad is located. So when you engage to 4wd the fork still moves so it doesn’t throw any nanny codes. It still thinks it’s working.

Have really liked the idea of the RCV axles. Was going to install them in our 2015 RUBI until it crashed. I am going to do the solid RCVs without question and the FAD delete dimple is serious Icing on the cake.

This and the AUX switched lockers will be done very soon. Would love to have this done for Ouray in August.

Thanks Roky and Limeade

 

[Az-jewel]

I got my wheel speed sensor replaced (evidently there is a wzit for the part everywhere. JKs don’t fit sadly, because theyre plentiful!)

Fixed the ESS, ABS, and cruise control issues, and initially the 4WD issue too. But when I’m wheeling and it’s been in 4WD for a bit (5-10 minutes) the SERVE4WD light comes back on! I don’t think its throwing a code, I’ve checked twice. The light goes out after I’m back in 2WD and have restarted the engine. If I’m in 2wd but haven’t restarted it, the light stays on.

Has anyone had this happen? Dealer couldn’t get it to reproduce and no code,

 

[TCogs1]

I got my wheel speed sensor replaced (evidently there is a wzit for the part everywhere. JKs don’t fit sadly, because theyre plentiful!)

Fixed the ESS, ABS, and cruise control issues, and initially the 4WD issue too. But when I’m wheeling and it’s been in 4WD for a bit (5-10 minutes) the SERVE4WD light comes back on! I don’t think its throwing a code, I’ve checked twice. The light goes out after I’m back in 2WD and have restarted the engine. If I’m in 2wd but haven’t restarted it, the light stays on.

Has anyone had this happen? Dealer couldn’t get it to reproduce and no code,

yes i had the same error issue when wheelin in Stoddard's wells CA.. .. I have not taken it in yet, but certainly got my attention.. I saw another thread on a work around using the aux switches to turn on the lockers... but I want to push Jeep for a fix... I am not sure what the real issue is.. lets keep pushing Jeep..

Thx

TC

 

[Az-jewel]

yes i had the same error issue when wheelin in Stoddard's wells CA.. .. I have not taken it in yet, but certainly got my attention.. I saw another thread on a work around using the aux switches to turn on the lockers... but I want to push Jeep for a fix... I am not sure what the real issue is.. lets keep pushing Jeep..

Thx

TC

yes i had the same error issue when wheelin in Stoddard's wells CA.. .. I have not taken it in yet, but certainly got my attention.. I saw another thread on a work around using the aux switches to turn on the lockers... but I want to push Jeep for a fix... I am not sure what the real issue is.. lets keep pushing Jeep..

Thx

TC

I did get this resolved, finally. Went to the dealer for a free oil change and they finally pulled a code for the serv4wd light I’d seen. It’s the FAD, front axle disconnect. Long story short, when the shop who trussed my front axle and did my regear reassembled it incorrectly and tucked the FAD inside the axle collar. Really frustrating as this is the second error the shop made reassembling my jeep!
it’s fixed now, $100 out of pocket, and I’m glad it’s working well.

hope you can find a solution to yours!

 

[HungryHound]

I recently had a lift kit installed on my 2018 JLUR. During the install process the front passenger ABS (wheel speed) sensor was stretched and damaged. This caused the following warning lights to come on: ABS, Trac Control, 4wd Serv. In researching this problem the simple solution is to replace the wheel speed sensor (Mopar Part #68394210AD). What I discovered is that that part is in scarce supply. The estimated delivery time from Mopar was 14 days and you can't find an after market equivalent anywhere. Although the JK sensor looks identical, it is not and does not work.

So the issue is this, while waiting for the part I have no ABS, Traction Control, and the big one...no 4WD! The wheel speed sensor error triggers a message that says "4wd temporarily unavailable" and lights up the warning light "4wd Serv". If you shift the Jeep into 4H it will not engage and the 4H does NOT light up on the center cluster. If you shift into 4L the gearing in the rear end changes but the TC does not lock and there is no power to the front diff. The front sway bar disconnect, and front and rear locker feature were also disabled. This was upsetting to me, because I desperately wanted to take the jeep out and test out the new lift kit, and didn't want to wait the 14 days for the part to arrive.

The Solution:

I was finally able to shift the jeep into 4H and 4L and use all of the Off Road Features.

In order to override the "4WD SERV" warning I did the following.

1. Put the Jeep in Park and turn the Jeep OFF
2. Shift the 4WD Lever to the 4H position
3. Start the Jeep
4. The Transfer Case should lock and engage the 4H before the computer has a chance to do a system check and discover the error codes. If it is successful the 4H will be lit on the center cluster. (the 4wd Serv light will stay on)
5. All 4H, 4L and all 4WD features will now be available and work normally as long as the Jeep is left running.
6. the ABS and Traction Control will still NOT WORK.

This hack may come in handy if you have a bad sensor on the trail and need 4WD to get home. Please let me know if you have any experience with this issue or any other suggestions. Thanks.

Thanks for posting this hack. I have an intermittent problem that is most likely a wheel speed sensor. 2,000 miles from home and wanted to hit some trails on the way back. No help from dealership in CA....2 weeks....don't care if you need to get back home.... etc.... so I'll give it a try next time I get the error and let you know how it went.

 

[swampflyer]

I recently had a lift kit installed on my 2018 JLUR. During the install process the front passenger ABS (wheel speed) sensor was stretched and damaged. This caused the following warning lights to come on: ABS, Trac Control, 4wd Serv. In researching this problem the simple solution is to replace the wheel speed sensor (Mopar Part #68394210AD). What I discovered is that that part is in scarce supply. The estimated delivery time from Mopar was 14 days and you can't find an after market equivalent anywhere. Although the JK sensor looks identical, it is not and does not work.

So the issue is this, while waiting for the part I have no ABS, Traction Control, and the big one...no 4WD! The wheel speed sensor error triggers a message that says "4wd temporarily unavailable" and lights up the warning light "4wd Serv". If you shift the Jeep into 4H it will not engage and the 4H does NOT light up on the center cluster. If you shift into 4L the gearing in the rear end changes but the TC does not lock and there is no power to the front diff. The front sway bar disconnect, and front and rear locker feature were also disabled. This was upsetting to me, because I desperately wanted to take the jeep out and test out the new lift kit, and didn't want to wait the 14 days for the part to arrive.

The Solution:

I was finally able to shift the jeep into 4H and 4L and use all of the Off Road Features.

In order to override the "4WD SERV" warning I did the following.

1. Put the Jeep in Park and turn the Jeep OFF
2. Shift the 4WD Lever to the 4H position
3. Start the Jeep
4. The Transfer Case should lock and engage the 4H before the computer has a chance to do a system check and discover the error codes. If it is successful the 4H will be lit on the center cluster. (the 4wd Serv light will stay on)
5. All 4H, 4L and all 4WD features will now be available and work normally as long as the Jeep is left running.
6. the ABS and Traction Control will still NOT WORK.

This hack may come in handy if you have a bad sensor on the trail and need 4WD to get home. Please let me know if you have any experience with this issue or any other suggestions. Thanks.

who in their right mind designed a piece of computer shit like this. We need a aftermarket source to reprogram and delete unwanted crap.

 

[HungryHound]

I’m still using the fad....... But the best way in my opinion, is to replace the 2 piece axle with a one piece axle like the rcv........

You can see the indentation on the axle shaft in the picture, that’s where the fork of the fad is located. So when you engage to 4wd the fork still moves so it doesn’t throw any nanny codes. It still thinks it’s working.

Is there not a way to mechanically lock-in the FAD on the JL? I locked mine in on my old YJ by removing the cover and bolting the mechanism in place.

 

[Roky]

Is there not a way to mechanically lock-in the FAD on the JL? I locked mine in on my old YJ by removing the cover and bolting the mechanism in place.

Not that I’m aware of. I wouldn’t want to throw a monkey wrench in the computer’s spokes anyway……. These JLs computer is very grumpy when you try shit like that. Was there even a computer in the YJ ??

 

[HungryHound]

Not that I’m aware of. I wouldn’t want to throw a monkey wrench in the computer’s spokes anyway……. These JLs computer is very grumpy when you try shit like that. Was there even a computer in the YJ ??

Just the ICM and the ECM as far as I know. I had them both bypassed.

I think I'm getting a Tazer for my birthday this month and will see how that does to solve my dilemma. Thought I was going to be stuck in 2wd on a trail earlier this week when the TCM decided to loose its mind. Not a good feeling when you're 15-20 miles from the nearest paved road.

 

[Roky]

Just the ICM and the ECM as far as I know. I had them both bypassed.

I think I'm getting a Tazer for my birthday this month and will see how that does to solve my dilemma. Thought I was going to be stuck in 2wd on a trail earlier this week when the TCM decided to loose its mind. Not a good feeling when you're 15-20 miles from the nearest paved road.

Yeah, the Tazer mini is the holy grail…… been using it going on 3 years now or more, can’t remember, long time…….that’s also how long it’s been since I used the ESS….. ?

 

[HungryHound]

Yeah, the Tazer mini is the holy grail…… been using it going on 3 years now or more, can’t remember, long time…….that’s also how long it’s been since I used the ESS….. ?

One advantage to the 4xe is no ESS system. Of course, I bought it for the Torque.

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