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"Service 4wd" light

127K views 134 replies 48 participants last post by  racers.mo 
#1 ·
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 ·
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?
 
#3 ·
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?
 
#5 ·
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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#6 ·
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...
 
#7 ·
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.
 
#8 ·
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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#10 ·
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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#11 ·
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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#13 ·
I did not have to get a SW flash since the replacement; and the error has not come back since.

Your results may vary, but I seem to believe that you will be fine without a flash based on my experience.
 
#15 ·
Once the error goes away: I assumed that all was good. But, because that wasn't enough for me: I took my truck to a nearby dirt road and gunned it in "sport mode" to make sure I wasn't getting one-wheel peel to confirm that the motor/system was working correctly.
 
#17 ·
Thanks for your detailed post.

I'm experiencing a similar issue it started with the light coming on and code C2221-00 being active, a TSB 21-008-11 for re-flashing the DTCM, so I take it to the dealer and pay their ridiculous diagnostic fees to get it looked at and re-flashed, only to have them call me back and tell me there are now 2 new codes both C148F-1D (Rear diff current out of range) and C2220-00 (Rear diff ECU internal). They told me it needs a motor/actuator $777.00 and an AWD module $600.00, and that the rear end is chattering.

So, I can understand the code C148F-1D for the the actuator, as it goes bad or gets gummed up it takes more current to turn it. Maybe the second code C2220-00 will go away once the current is in range. I've had a slight vibration since I bought this used as well, so maybe the rear end has an additional problem as well. In my case maybe a used unit swapped in as a whole will solve most issues.

Does anyone know where to buy a new motor like Roby did to swap into this as a start?

How can I find out if the rear end is actually making noise and its not just the motor making it?

Anything else I should do first?

Thank you for any help on this...

Jocco,
 
#19 ·
This motor can be found at a more reasonable price on E-bay in new form, OR, you can purchase a whole eLSD (rear transaxle) unit with the motor attached from a junk yard and salvage just the motor from the sub-assy and install on your vehicle.
 
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#20 ·
I found more information about my traction control question on another forum here:
"Sport" Mode question - JeepForum.com

"Sport mode biases the transfer case to give you more of a rear wheel drive feel. It does not turn traction control completely off but Jeep engineering does not provide more information. The light warns you that traction control is not completely enabled."
 
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#22 ·
Hey stician,

Please feel free to reach out if you need additional assistance. Let us know how it goes at the dealership!

Kori
Jeep Social Care Specialist
 
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#25 · (Edited)
So I finally got around to taking the motor out and looking at it. The shaft was somewhat stiff to turn but not jamming in any way.

I looked up the numbers that were on the tag for the motor and could find nothing that matched up to it. The dealer part number 68084266AB that fits my 2011 I found on the internet fine. The lowest price I found was $288 (Dealer $662) from a mopar overstock type dealer.

When I was looking up the codes I had found some information about the measured circuit out of range C148F-1D and that it needed a flash, which I got back then. Thinking about the error I started to think that maybe the motor was just gummed up and the commutator and brushes were dirty causing it to draw higher than normal amperage through the circuit.

http://www.wk2jeeps.com/tsb/tsb_wk2_2100114.pdf

I took the 2 torx screws out of the cover and carefully slipped it off. The brushes are in the aluminum housing end and all that is on the other end is a small bearing that fits into the housing far end. The magnets are quite strong so be careful taking it off. I tapped both the housing and the cover lightly upside down with a small plastic mallet and tapped upside down on the flat of my vice, careful not to do it too hard. A lot of carbon dust and a couple of small bits like leftover plastic or carbon from the brushes fell out. The motor now spun nice and free by hand.

I attached a cordless drill to the motor and spun it while using commutator paper to sand the commutator back to a nice shiny copper and to re-seat the brushes. I blew out the housing and cover and wiped clean with a cloth inside. I reassembled it and the motor now spun pretty free with no binding or stiffness.

I did not put any lubricant into the bearings, they are sealed and felt ok to me, although those could probably be replaced as well.

I put it back into the vehicle, reconnected everything and the error condition was gone. It has not come back since and I can change driving modes without any issues.

I was pretty comfortable doing this as I had worked on electric forklifts a long time ago and had to clean the electric motors this was all the time. What else did I have to lose, I was queuing up to buy a new one anyway.

The difficulty level for both R and R as well as the cleaning was pretty low. Unless you try to pull the armature and circuit board out of the aluminum housing you really can't break anything more than it was. Just be gentle when cleaning it.
 
#26 ·
OK, to close the loop on this the repair I did, it lasted about a week and the light came on again. So I searched for and found the motor for my part number at the site below, very reasonable cost of $220 compared to the dealer and shipping was only $10. The part is on sale right now too for $10 less...shipping was fast too.

Mopar America
950 HWY 66 South
Kernersville, NC 27284

Mopar Motor - 2011 Jeep Grand Cherokee - 68084266AB : Genuine Mopar Parts For Dodge Jeep RAM Chrysler

It's been over a month or so now and the light remains off and it driving great.
 
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#27 ·
This is a god send if it works. I've been dealing with this "Service 4WD" for about a month and a half looking at various items under the Cherokee.
I have a little over 131,000 mile on my 2011 5.7 Overland and hope this will fix the issue.
Thanks for the write up, part number, and cheaper source for the part. :)
 
#28 · (Edited)
I've had this exact issue (Serv 4WD, Esc Off, Check engine) come up intermittently recently. Local shop ran for codes and said there were none thrown. Check engine light was off at that time. Then just this week, there is suddenly a loud ticking coming from under the vehicle. Tap the gas, 10 ticks, then stop. Tap the gas, 10 ticks, then stop. Loud. And the front end feels like its locking up at full turn. Will actually stop the vehicle at full turn. I can give it gas and it will jerk on through a turn. Almost feels like when a front end locker is engaged (perhaps?). All while in normal driving mode.

I'd love for this to be just a transfer case motor at this point. And HUGE thanks to OP and all that contributed in this thread. Any ideas?

2012 Laredo 3.6L, 4wd, 92k miles
 
#29 ·
Maybe front wheel bearings and sensors?

I was thinking of just doing mine as well when I attack the front brakes. The front hub assemblies are relatively cheap, about $60 per side, and come with the wheel sensors. Another poster had mentioned bad wheel speed sensors could also trigger the ABS and SERVICE 4WD system error.

Luckily, I have not had a check engine light come on with the other two. I will try the ESLD motor first then move to the Wheel sensors?

Anyone have a part number and procedures for the ELSD Solenoid?
 
#30 ·
Wife's WK2 is now getting the SERV 4WD light intermittently. Dropping it off at the dealership today for a service appointment tomorrow. Will update.
 
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