I just tried the fuse pull trick and the issue remains. I'm thinking its probably the transfer case motor, any way to tell without taking it to a dealer? Will the blue driver app read codes from the FDCM?

 

Will the blue driver app read codes from the FDCM?

I have a Bluedriver and I did have a 4x4 code not related to N23 etc. It was a clutch pack code but it caused me to get the Service 4x4 message and made my 4lo stop working. The Bluedriver DID read the code and DID clear the code. It also read and cleared a wheel pressure sensor code and clear it. So that is pretty good. Will it read everything?? Don't know.

As far as the fix is concerned.... I have not seen one for sure. That thread is soooo long and the results are spotty. Replacing the FDCM with a "PRE-N23" controller that has not had the N23 seems to work for most... but those are very hard to find and what guarantee do you have that that is what you are really getting.

Mine has not had the N23 or any of the other "fixes" and it works great. Since I have not had the N23, I'm not the best person to comment...but I wanted to say a word about the Bluedriver.

 

Bluedriver should be able to pull the N23/P73 error code if that is the problem. That code is C140F

C140F-TRANSFER CASE RANGE POSITION SENSOR ERRATIC PERFORMANCE

However with the N23 problem the "Service 4x4 System" error normally will only show when you try and actually engage 4low. It does give you the error on start up or while driving.

One test is the fuse pull trick. If N23 is the problem this will clear the error from memory and 4low should work at least for a few tries. Once the system gets it 3 times its back to the error message. Good write up on the "Fuse Pull Trick" by Troy123 here http://www.jeepforum.com/forum/f67/n23-recall-issue-no-4-low-1561787/index91.html#post20486321

If you don't want to pop for a reader now most auto part stores have them and will not charge to check for errors. May not be N23 related. The "Service 4x4 System" can be caused by a lot of things. So you need to get the codes before you start tossing parts at it and hope you got the right one.

 

If you don't want to pop for a reader now most auto part stores have them and will not charge to check for errors. May not be N23 related. The "Service 4x4 System" can be caused by a lot of things. So you need to get the codes before you start tossing parts at it and hope you got the right one.

That depends on what scanner they use. Out of curiosity, I once took my WK into the most popular auto-repair shop in our small town... they have one of those real fancy expensive cabinet model type scanners that do anything...but when they came out to do my "free scan" that they advertise, they brought out a hand held "Auto Xray" brand...and it showed no codes. Took it over to NAPA and they did the same thing using a different brand cheap scanner.... no codes. Went home and hooked up my DS-708 and pulled and cleared my Clutch Pack code. This was before I bought the Bluedriver. The DS is clearly better, but the BD is easier to use and more convenient.

 

Awesome, good info. I ordered the blue driver and will post my codes on friday afternoon when it arrives, I didn't realize there were more codes for the service 4wd but it makes sense!

I did take the connector off today and cleaned it and put some dialectic grease in it. One of the pins had some corrosion on it so I may be having an issue related to that. Didn't fix the message though!

 

With me, I had the dreaded N23 recall done, then my service 4wd system light came on. Fuse pull trick worked for a couple months, then it stopped working. Took the jeep in for the latest update to the n23 recall. The shop didn't so anything about looking at the code or anything. They were going to just let me leave and not say anything. When I asked them about the the code, they said that it was stored in the system and he could not delete it. I was kind of pissed that he wasn't going to say anything, and then they said they weren't going to do anything about it because all the "recall" was, was for them to update the programming. Which they did, so by their eyes, they were done. Even though the recall said to replace as needed....which apparently meant to have a STAR case opened with chrysler..etc etc. Pissed me off even more that the dealer acted like they had no idea what I was talking about. They didn't "know" anything about the n23 recall causing problems or anything.

That being said, the lasted update (july 2014?) to the n23 recall fixed the 4lo problem. I have not had an issue with the transfer case since I had the update done. Which was mid 2015

 

Update

My Bluedriver scanner just came in the mail today. It read my codes no problem.

Other than a code for my passenger mirror circuit, here's everything that I've done up to this point (even before getting the scanner)

-replaced wheel speed sensors last week (there was a stored code from them which cleared just fine)
-service 4WD message came on during road trip, 4-lo did not work. Was driving through rain for a few hours
-took off connector to transfer case motor, noticed some corrosion on terminals and connector (photos attached).
(see bottom left connector)

(photo of pins)

-cleaned connector and terminals with electrical contact cleaner, put back together with dielectric grease to seal out moisture
-scanned with blue driver and retrieved following codes:
U0114 - Lost communication with four wheel drive clutch control module
C1407 - Transfer Case Brake Control Circuit Low
C1438 - Transfer Case Differential Clutch Worn
C1405 - Transfer Case Range Position Sensor Circuit High
C1406 - Transfer Case Brake Performance
C140F - Transfer Case Range Position Sensor Erratic Performance
- cleared codes in driveway, 4 - lo shifted just fine in driveway several times
- checked for codes again, only code that came back was
U0114 - Lost communication with four wheel drive clutch control module (i did not clear before next steps)
- drove to muddy/slippery area to test 4 wheel drive and 4 lo
- 4 wheel high works just fine, gave it throttle to be sure front wheels engaged
- tested 4 - lo operation, DID NOT WORK, Service 4wd Message showed up
- checked for codes with Bluedriver, found:
U0114 - Lost communication with four wheel drive clutch control module
C1405 - Transfer Case Range Position Sensor Circuit High
C140F - Transfer Case Range Position Sensor Erratic Performance

So, I'm thinking I could have a few issues but I'm not sure how I should approach them.

The U0114 code is concerning in that I have no idea what to do about it.
The C1405 and C140F codes, I am thinking that I should go back and clean the connector again just to be sure I did a good job, and I'll also check the connection to the FDCM under the seat. That or the motor is actually bad and I can replace it.

Any ideas or suggestions?

 

It's pretty wet outside so I'm going to wait to crawl underneath the jeep to clean the connectors again. Instead I just did another quick driveway test, I cleared the codes and it shifted into 4-lo just fine. I did it a few times then re-read for codes and the "C140F" code came back, even though it was letting me shift into 4-lo (in the driveway at least). Didn't bother with another test drive as I think I'll get the exact same results.

I love the blue driver app...thanks everyone above for the info and for recommending it. It scans kinda slow when searching every module but its pretty powerful stacked up against my little Actron scanner

 

Having only the C140F error left is the unfortunate sign of the N23 recall. Almost all early problem with N23 were solved by the updated procedure stressing things like outside power source during the re-flash and clearing the C140F error at least three times. But if this error can't be cleared assumption was that the circuit board of the actuator had cracks in the solder connections...reason for the recall.

Aside from a revisit of the connector i would try is repeated clearing the C140F error. But if it can't be cleared most likely means you have a wonky actuator. But the updated program that came with N23 has a very small tolerance range for the voltage signal from the actuator that lets the FDCM know the position. The bad connector is a known..hope another cleaning does the trick.

But if not you can clear the error (fuse pull or with your Bluedriver) whenever you need 4low, replace the actuator or find a pre-N23 FDCM.

Although actuator replacement should be covered under the recall Chrysler "Customer Service" have more moves than a North Las Vegas stripper to avoid paying for it...Not going to happen.

 

Since you now have a Bluedriver, I recommend that you log a whole bunch of live data while driving in various settings (after you get your current issue fixed.) Save these logs to dropbox, or your computer or whatever. Next time you have a mysterious problem, the logs of normal driving will help track down the problem.

Live logging is very easy with the BD.

 

Great idea! Grab a baseline while everything's good.

 

I think I must have had water in my connection. It definitely had some corrosion and after cleaning I haven't had the issue come back. Thank goodness for the Bluedriver and being able to read and reset those codes.

I've shifted in and out of 4 lo and have driving off road with no more codes. I hope it's all fixed for good! Thanks for the info everyone!

 

Just wanted to update my situation.

I had the Service 4X4 light click on about a week after I bought my 2007 WK CRD used in January 2017. I tested 4 Low prior to the service light and had no issues. Light came on and off occasionally and I lost 4 Low (if service light wasn't on, attempting 4 Low would trigger it). After multiple dealership visits I finally got my selling dealer(Toyota) to pay for the work to be performed by a Jeep dealership. Jeep initially said new transfer case motor, Toyota pulled codes and actually researched the N23 problem and sent me back to Jeep, Jeep still said new transfer case motor.
Records show mine was already N23 and P23 flashed so I asked jeep to simply try redoing it. Seems they didn't really like me telling them how to do their jobs as they were quick to reply it needs a new transfer case motor.
I finally got Toyota to pay for a new transfer case motor installed at Jeep and have not had any 4 Low issues since. It has only been a few days but Ill update if things change.

Sorry this likely wont help much as I still think it was N23 related but thus far a new transfer case motor has fixed my 4x4 service light and loss of 4 Low.

PS For anyone dealing with Grand Cherokee (WK) issues; these are aging machines, they need maintenance and they'll have issues. Still, I love my WK almost as much as I love hearing people say "diesel Jeep?"

 

I love hearing people say "diesel Jeep?"

Ditto this! I had another on just the other day. One day I had a station attendant come running out screaming at me... "Stop Stop!! That's diesel fuel!!" He was really trying to save me. Ha. Surprised him.

 

I did N23 early on and at that time dealer replaced TCAM because it was throwing a code, I think the one cited above, C140F-TRANSFER CASE RANGE POSITION SENSOR ERRATIC PERFORMANCE. Then later P73 was done, at least a year ago. Since then no problem. Everything is going to be just fine now. :wink2:

 

"Service 4wd system" final fix?

Hello All, I bought my WK in September 2016. Recently it started to show the "service 4wd" when ever I engaged 4Lo. I could here the transfer motor working for a while, and it did engage 4Lo, only the message appeared. If I shot the engine down, opened the door to shut off all electrical power, and then restart the car, everything was as good as new. until I decided to engage 4Lo again.

I took my jeep to a good friend´s shop. My jeep has not had ANY recall done to it... It only showed CODE C1406.

After analyzing the wiring, and taking the transfer motor out for cleaning... They decided to open the transfer motor, to their surprise thesprings that hold the carbon bushes where out of place. They assembled the Transfer motor back together correctly and the problem has gone away. I will update this thread if the problem comes back... They saved me 400 dls for a new transfer motor.

 

What is the easiest way of testing 4 wheel drive?

 

I just want to add my experience for anybody reading through this in the future. I purchased my WK in September 2016. Fortunately, my jeep hasn't had any recall work done to it. I have used 4Lo, 4 or 5 times, but then suddenly, any time I tried to engage it, even though I could hear it working, it would trigger "service 4wd", shutting off and back on would erase the code. I took it to my friends shop where after a good analysis, they determined that the springs which hold the carbon bushings of the transfer case actuator motor where out of place, they cleaned and re built the transfer case motor properly, and the problem went away!

Recently however, I found two new problems...I dont know if they are related or not, But some how they are both fixed.
First problem, I could not control the interior overhead lights by command with the switch behind the steering wheel. Although not a mayor problem... definitely a weird one.
Second Problem,
After losing traction slightly on my 255/70 tires on tarmac in light rain, on a mountain road... maybe 10-15 seconds later, the "service 4wd" code appeared... I turned the jeep off and back on, the message went away, but after a minute, it came back on. I drove over maybe 200ft of steep uneven muddy hill climb without much effort, even though the service 4wd light was on. 4wd must had been working because my friend in his stock Rubicon had a hard time climbing this (probably do to tires), but he did have to engage his lockers.
Later I did the fuse pull trick, however I had no way of checking which one, I pulled the FDCM pink fuse, which is under the hood in the other fuse box next to the one I should have opened, I drove for 3 minutes, replaced it, turned the jeep off and on and the problem went away, I tried 4Lo, and everything worked!
I drove for over 5 hours on dirt roads and some pretty bad roads too. The message never returned. When I got home, I discovered that I could now control the overhead lights!

What do you guys think happened?

 

Don't ask questions....it works and leave it at that lol

 

Pre n23 NON PROGRAMMED FDCM for sale

Well...so much for being a jeep owner since the 70's!! After struggling with N23 and numerous P73 reflashing on my 2008 Jeep Grand Cherokee, at $110k miles it had warped heads. That cost me over $3000 last month. Last week the transmission started going. I could not deal with all the expense. Much to my dismay, my beautiful red jeep was traded in. The good news is that I have a PRE N23 FDCM to sell to someone else that could use it. I purchased it a few years ago and it is from a totaled jeep that had been sitting in the bone yard and had not be reprogramed. It worked EVERTIME!! I am selling it for $110, including shipping. It will fit a 2008-2010 Grand Cherokee, with NV245 transfer case. Your FDCM MUST end in 129AH for this to be compatible. Please be sure its the one you need as no returns will be made. Thank you all for the years of knowledge and support.

 

Well...so much for being a jeep owner since the 70's!! After struggling with N23 and numerous P73 reflashing on my 2008 Jeep Grand Cherokee, at $110k miles it had warped heads. That cost me over $3000 last month. Last week the transmission started going. I could not deal with all the expense. Much to my dismay, my beautiful red jeep was traded in. The good news is that I have a PRE N23 FDCM to sell to someone else that could use it. I purchased it a few years ago and it is from a totaled jeep that had been sitting in the bone yard and had not be reprogramed. It worked EVERTIME!! I am selling it for $110, including shipping. It will fit a 2008-2010 Grand Cherokee, with NV245 transfer case. Your FDCM MUST end in 129AH for this to be compatible. Please be sure its the one you need as no returns will be made. Thank you all for the years of knowledge and support.

I'm sorry about your jeep, but I am interested in the FDCM and have sent you an email just a minute ago (could not PM). Let me know if you did not get the email. Thanks!

 

I got in my 07 and got the service 4 wheel message never had it before car sat for a week before this. Got these codes
I did the transfer case motor still get the message. Motor works, I wonder if it’s the FDCM. The car is old but in good shape and I’ll keep it going but I won’t dump unnecessary money. I’ll just keep trying to figure it out it’s just a weird situation
U0114 Lost Communication With Final Drive Control Modu
STORED

Transfer Case Range Position Sensor Circuit High

Rear Differential Control Circuit 'Current' Performance

Front Differential Control Circuit 'Current' Performance

(FDCM) Final Drive Control Internal

Drivetrain Supply Voltage Circuit Lo