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Service 4WD

2K views 27 replies 15 participants last post by  kf4zht 
#1 ·
Every time I turn on the car I get a service 4wd message, yet it's driving completely normal. I've been through snow and everything without any noticeable issues, so I'm wondering what could be causing it. It came on after I drive through a really muddy road. Could a sensor have gotten dirty or something?
 
#11 ·
Get an OBD2 scanner on sale. The diesel engine wk doesn't allow the key dance. Had this question on site for years. No answers except from gas engine people.
Your service notice is due to the transfer case actuator circuit board or if you got the recall flash done. Search on the forum.
 
#8 ·
Find a friend with a Maxidas DS-708 scanner. It will read and clear all the 4x4 codes... its kinds of spendy but if it saves you one trip to the dealer, that could pay for it. (No, I don't work for them.)
 
#12 ·
101gargoyles said:
Get an OBD2 scanner on sale. The diesel engine wk doesn't allow the key dance. Had this question on site for years. No answers except from gas engine people. Your service notice is due to the transfer case actuator circuit board or if you got the recall flash done. Search on the forum.
Mine is a gas engine. I had the recall done but I thought that only effected the 4 low? How would I go about doing the actuator board?
 
#13 ·
If you can still shift into 4low - it is not a N23 recall or transfer case actuator problem. You really need a good reader to pull the error codes to see what is going on. Traildash should do that.

The key dance is great but doesn't display many code.

The deal with the actuator board and the N23 recall is some actuators had cracks in the circuit board tracings that caused an inadvertent shift into neutral when starting. A problem when using remote start for sure. But the N23 problem only shows when trying to shift into 4low or setting the transfer case to neutral (for towing etc.). Only gives the error when you try to do either of these.

BTW - you can't replace the board itself. Have to replace the actuator. But if N23 related should be covered under the recall... but again. Does not sound like a N23 problem.
 
#18 ·
I had the N23 issues, the P73 fix and then more issues, and finally this past Friday the dealer had it in for the ignition switch recall and did some other programming for the transfer case, and this time is seems to have resolved the issue for good. I will let you know if it comes back, but for now I no longer am getting the light and I have 4xLo on demand...
 
#19 ·
Hey JF97,

TSB 21-022-14 REV. A may relate to your vehicle:
SUBJECT:
4WD Lamp Illuminated and Diagnostic Trouble Code C140F Active in Final Drive Control
Modules (FDCM) Memory
OVERVIEW:
This bulletin involves verifying FDCM software level and then flash reprogramming of the
FDCM with new software.
MODELS:
2005 - 2010 WH/WK Grand Cherokee
2006 - 2010 XH/XK Commander
NOTE: This bulletin applies to vehicles that have had Recall N23 performed.
SYMPTOM/CONDITION:
Customers may indicate that the "Service 4WD" indicator in the instrument cluster is
illuminated. They may also indicate that the transfer case will not shift from 4WD High,
4WD Low, and/or Neutral once the lamp is illuminated.
Further investigation identifies that a Diagnostic Trouble Code C140F is stored or active in
the Final Drive Control Modules (FDCM) Memory
 
#20 ·
JeepCares said:
Hey JF97, TSB 21-022-14 REV. A may relate to your vehicle: SUBJECT: 4WD Lamp Illuminated and Diagnostic Trouble Code C140F Active in Final Drive Control Modules (FDCM) Memory OVERVIEW: This bulletin involves verifying FDCM software level and then flash reprogramming of the FDCM with new software. MODELS: 2005 - 2010 WH/WK Grand Cherokee 2006 - 2010 XH/XK Commander NOTE: This bulletin applies to vehicles that have had Recall N23 performed. SYMPTOM/CONDITION: Customers may indicate that the “Service 4WD” indicator in the instrument cluster is illuminated. They may also indicate that the transfer case will not shift from 4WD High, 4WD Low, and/or Neutral once the lamp is illuminated. Further investigation identifies that a Diagnostic Trouble Code C140F is stored or active in the Final Drive Control Modules (FDCM) Memory
well I'll have to see then! Thanks!
 
#22 ·
I continue to have SERVICE 4WD SYSTEM displayed. Right now I have a diagnostics unit hooked up to the Jeep while I drive around to try an capture why since the first recall this keeps happening. I have also had the latest updates.

That being said, the dealer said they did do some work on the connector even though there was no sign of corrosion. I did some googling and I found a reference to a TSB from 06 that mentioned it possibly being the connector, one of the repairs is to replace it with a new connector that has gold plated contacts while conducts electricity better in turn won't cause resistance to trigger the code being displayed.

Since I last brought it in and had the diagnostics computer attached , the code came up, but at the next key cycle it went away, so it's quite possible the problem may be related to the connector and a very sensitive program in the FDCM. So the saga continues for me... Very disappointed I hope it's just not a coincidence and possibly the road to a solution.
 
#25 ·
you "may" find this helpful...

don't know why, but, be gentle if you reply.
These are not uncommon problems that you've all described, and MANY of us have had the same issues, and right away, we ALL have thought, why me, why MY WK??..how come it comes up with these weird and untenable issues with it's electrical systems.
What did it for me, was the "service 4wd" issue...service what??...I too got the recall notice to reflash the all wheel drive module, and hesitated, as I have done a FULL ECU performance upgrade with a great performance shop in Oakville, and it's NOT uncommon for dealerships to COMPLETELY ignore your request/demand, to NOT touch the ECU in their "wisdom".
I did some digging...seems a common thread was the lack of continuity in the power supply in the vehicle.
We ALL have stories about our batteries, what we got, where we got it, how much we "saved" by getting one at some mysterious "bargain" location, or on sale, or "whatever.
This past year, my 2008 WK CRD was STILL running the same battery...lasted a long time in MY books, and just as a "preventative" measure, I thought..."what the hell, it's time for a new battery"...don't ask me why?....I LIKE long lasting "everythings" when I buy them...cheaper is NOT better in the long run!
I picked up a: Year: 2008
Make: Jeep
Model: Grand Cherokee
Engine: 3.0 Liters 182 CID V6
Model #: PC1350
BCI #: 49
Install Notes: No specific installation notes
Battery made by Odyssey, from a great battery dealer in Hamilton, well made, great reputation, and kinda expensive!!
Within 3 days, all my WK "troubles" seemed to miraculously vanish...INCLUDING my "service 4wd" message......how can this be??...le's just say in MY case...it COULD be, and it seemed to be, and for now, I'm going to leave it be!:D
 
#28 ·
I fought this for years and tried every different tuner and just got frustrated. Even a snapon solus wouldn't clear it. I didn't have the coin for the Maxdas unit. Finally picked up the bluedriver one that someone mentioned. It pulled the normal n23 codes as saved and the clutch performance as active. Cleared them and with over 1000 miles on it the 4wd still works. The doohickey is small enough I can keep it in the car all the time and just need my phone.
 
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