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  #1  
Old 11-12-2015, 04:13 PM
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"Service 4wd" light

Awesome.

So; yesterday, I crossed 108k in the WK2. As I did, I pulled into traffic and I received a "service 4wd" error on the display, and simultaneously the traction control off light turned ON (as if I was in "SPORT" mode).

I did the turn on///turn off the car, and attempt to "reboot" the vehicle. It stayed off until this morning, and came back on during my commute to work.

I went to the local A-zone and got the code-reader to see if I could get a diagnostic code to point me in the right direction.... just as suspected, they did not/could not get anything from the DTC port.....

SO:

I will crawl under the car and see if there are any electrical connections loose (not going to hold my breath....). From there, I will take a look at the electrical connections with a multi-meter to make sure that they are getting continuity...

Any other suggestions in my base-level trouble shooting???

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  #2  
Old 11-13-2015, 05:04 PM
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Re: "Service 4wd" light

I have a friend who can pull codes from the car: I popped by his office today.

Codes that were "status = stored" are:

C148F-1D - Rear Differential Measured Motor-Circuit current out of range
C149-00 - Rrear Differential Actuator Initialization Failure
C2220-00 - Rear Differential ECU Internal

It was rainy last night, so I wasn't going to get under the car to look around. It was rather cold today - and we may have a little warm-up tomorrow. I will take a look at the various electrical connections to the rear-diff. I am not ready to make conclusions, but I believe that we may be looking at replacing either the motor or the electrical control board on the rear-diff in the near future.

Any others out there tackled this job on their own?
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Old 11-16-2015, 09:57 AM
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Re: "Service 4wd" light

A number of views, but no real bites? I am surprised that nobody on this site has tackled fixing this on their own...

Anyhow, I crawled under the car this weekend to take a look at the rear diff -- all wire/connections were secure and OK.

My search results on the site have yielded a number of "I took it to the dealer, and they did this-n-that and it is fixed now..." Which has included a couple people saying that there was a wire connection that had disconnected itself.

Anyone have an experience that is similar that they would like to share?
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Old 11-16-2015, 08:55 PM
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Quote:
Originally Posted by Robey5 View Post
A number of views, but no real bites? I am surprised that nobody on this site has tackled fixing this on their own...

Anyhow, I crawled under the car this weekend to take a look at the rear diff -- all wire/connections were secure and OK.

My search results on the site have yielded a number of "I took it to the dealer, and they did this-n-that and it is fixed now..." Which has included a couple people saying that there was a wire connection that had disconnected itself.

Anyone have an experience that is similar that they would like to share?
Was this a one time thing? I've had it happen a couple times before at periods really spread out. It was an electrical surge that kind of threw it out of wack. K had some bcm codes that came with it but they went and it didn't repeat. Hope that helps
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Old 11-19-2015, 01:30 PM
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Re: "Service 4wd" light

This "service 4wd" light/error (unfortunately) is not a one time thing.

It throws this error 8 out of 10 times that I start the vehicle. Usually -- it throws the code right at start up. Some times, it will wait for several miles (10+) and then throw the error, and some times it will not throw the code at ALL. It is not really connected to any specific event (...although the majority of the time, I put the vehicle in "sport" mode when I drive it when there is not snow/ice on the roads...)
It does not seem to matter if I put it in sport mode or not - some times it will throw the error, some times not.
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Old 11-30-2015, 09:08 AM
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Re: "Service 4wd" light

I got under the Jeep yesterday and checked the electrical connections at the transfer case as well as at the rear diff.

I was able to confirm that these connections were as they were supposed to be (tight/secure/together) and I was able to disconnect the ones that go to the motor(s) and hit the pins with dielectric grease - and then re-connect.

No dice. Still throws the error code more often than not, and was dropped at the dealer this morning on the way to the office. We will see whats next...
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Old 11-30-2015, 04:38 PM
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Re: "Service 4wd" light

Well; we have a diagnosis from the dealership (...costing me $140).

Rear differential motor for the eLSD system "is in need of replacement". ...and the software for the controller needs to be re-flashed.

The "estimate" is $900 at this point to replace the motor and re-flash the software on the module.

I of course must know: what does the motor cost??? The technician informed me that we're at $662 for the motor. ... not a very satisfying price point for me, knowing that the "cost" to make this motor is well less than 1/10th of that price point. ...And, I can install a motor on the rear diff any old day of the week. I am unsure how to re-flash the SW to make this new motor operate however....

...off to find a "6808 4266AB" motor.
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Old 12-01-2015, 09:17 AM
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Re: "Service 4wd" light

A little research on this motor...

I was able to find a lower price on flea-bay ... ($450) ... for a new one (Chrysler hits you for $662, and there are people out there selling the exact same one for $450: sounds a little fishy, like someone "stockpiled" some of these motors...)

...I was still unable to justify such a price for a simple brushed motor with a electro-mechanical brake.

so, I dug a little deeper and found that I could get a whole rear differential for $300, and I could harvest the motor off of it from a "scrap yard" locally. (the scrap yard does not want to just sell the motor off of the diff, they want to sell the whole "carrier").

Still not satisfied with this price - I will continue to investigate other options.

From what I've been informed, I am going to have to re-flash the differential module once I have installed the new motor so that it notices that this 'new' motor is OK. Does anyone know of a different initialization process?
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Old 12-01-2015, 09:41 AM
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Re: "Service 4wd" light

Thanks for answering your own questions and for getting to the bottom of this. I don't have this problem but it could help someone down the road.
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Old 12-07-2015, 03:25 PM
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Re: "Service 4wd" light

I have a *new* motor in hand.

It did not cost $662. Nor did it cost $450; but it was still expensive.

I will install it tonight, and take a couple pictures....
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Old 12-08-2015, 11:34 AM
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Re: "Service 4wd" light

Here goes:

I backed my JGC into the garage and threw on my insulated carhartts; turned on the furnace in preparation of working on my back.

I put a set of various tools on my little stool/cart not positive what would be needed, but knowing that I would be pulling 4 allen-bolts and 2 electrical connections.

Before I slid underneath the jeep: I put it in O/R-3 height and applied some dielectric grease in the connector of the new motor (on the connector-pins, 10 of them I believe).

The motor is located (roughly) on the left side of the rear differential, and the electrical connectors are above the diff, wires are routed above the diff.

I used only one metric allen wrench for this job (M4, I believe) and removed the 4 bolts that connect the motor/brake assy to the transfer case. As you will see, all 4 bolts are the same length, and none of them used thread-locker, nor did they use a washer. Hence, they went back in there the same way.

I pulled the connectors, which are secured to the differential by way of a 'x-mas tree' connector (3 of them). I then pulled the spent motor off of the differential (covered in about 110k miles worth of road debris) and put it on the floor to do a comparison of old versus new. Then, I saw that there was a small key-way/roll pin that secures the output shaft to the assembly. So, not being positive if there was a sensor or encoder inside the motor, I was sure to take the old motor out STRAIGHT (no twisting), and put the output shaft on the new motor in the same position (roughly 10:00).

At this point, I had the 'old motor' out and took a look at the interface where the new motor was to be installed. Knowing what I do about brushed motors and electrical things and the way that they are not likely to work well with oil and water (etc) I grabbed a rag and cleaned the very small amount of oil that came out of the differential area where the new motor was going to be installed.

Armed with my new motor, I slid under the truck and installed it into the rightful spot. I routed the electrical connection just the same as the old.

4 bolts were cleaned up with a rag and then snugged up on the housing (I do not know what the torque was to install, but they were not very tight, and the threads were pretty fine, and going into the aluminum differential housing).

Total time invested:
1 hour (including the test drive - which revealed that the "serv4wd" light did not pop with the new motor installed). ...At this point, I am not SURE that I am going to go to the dealer to get the SW flashed as recommended by the technician. If the light does not come back on over this coming weekend, I am not going to get the system flashed.

Total "PITA" factor: very low. The electrical connector that has 8 pins in it was a little tougher to get correct.

A comment about parts availability: I am quite surprised that this motor is not available (yet) at a local DIY parts store. There are a number of motors on this vehicle that are brushed and have potential for failure, so I can imagine that there will be a way to get these from a place like A-zone or O-rileys or the like in the future.

I later tried to spin the shaft on the "old" motor, and found it to be VERY hard to move, so I bet there is a bunch of oil in there or something. Perhaps a root cause analysis is in order at a later date.

If anything: I hope that this little project helps someone looking to tackle the same 'problem'.
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Old 04-09-2016, 12:00 PM
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Re: "Service 4wd" light

Robey did you end up needing to get a flash after the install? Has the light come on since?
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