Why does (Service 4 wheel Drive system) keep coming up on the warning panel and stopping me putting it into 4 wheel drive low?


Asked by Willow35 Jul 22, 2014 at 07:50 AM about the 2005 Jeep Grand Cherokee

Question type: Maintenance & Repair

Cannot select 4 wheel drive low due to alarm and message of (Service 4 wheel drive

3 Answers


Here is a paragraph I found on line: You will have to have it checked with a scan tool. ADDITIONAL INFO: This is a known problem with newer model Jeeps. It MIGHT mean this is an issue or it may not. I have had this problem with my 2006 WK (Commander) 5.7L and my 4WD still functioned properly. Unfortunately your only viable option is to take it to a 5 STAR Dealer and have it diagnosed, since this is a specialized system and most independent shops do not have the StarSCAN tool to service it. Chrysler DOES know about this problem and issued a Technical Service Bulletin on the subject.Please keep in mind that while Chrysler DOES know there is a problem, they are not required to fix it at no charge if it is not within a warranty period. This particular problem is NOT a recall.


Here is another solution I found. You may want to try this one first. I got the fix for this problem from another site. The actuator in front diff gets corroded from not being put in 4low enough so it stays stuck in. Also shortly after the N23 recall was done. Take the #25 fuse (e-diff) out in fuse box under the hood closest to the firewall. The "Service 4wheel Drive System" come on the dash steady. Drive around for abit then put fuse back in with engine running. Shut off engine then restart. My problem was fixed and it goes in and out of 4low now.

3 out of 3 people think this is helpful.

Jeep N23 Recall problems For starters, I have a 2006 Jeep Grand Cherokee Limited that I purchased as a vehicle to tow behind our RV. I have had no problems towing this vehicle 4 wheels down for seven years until getting the Jeep N23 recall fix. Since then it will periodically give the message to “Service 4WD System” when doing the procedure to put it in 4WD neutral for towing. We have actually had to leave our Jeep on the street when we had a service appointment for our RV 120 miles away because we couldn’t tow it. It doesn’t take much to find that there are thousands of people affected by this problem as quick Google search for “Jeep Service 4WD System” gets thousands of hits. The first few zero in on the problem for many started after getting the N23 recall fix. It turns out that after the fix the affected vehicles will eventually not be able to put the vehicle in 4WD neutral for towing or in 4WD LOW for off roading. The reason for the recall is that a cracked circuit board that controls the 4WD Low and 4WD Neutral can cause the vehicle to go into neutral when stopped in park. This could result in the vehicle rolling away when parked – across a parking lot or worse, down a hill. That of course, assumes that people don’t use their emergency brake when parking. So instead of fixing the cracked circuit board Jeep came up with a software fix. You DON’T FIX CRACKED CIRCUIT BOARDS WITH SOFTWARE. So what did they do? Apparently they fixed software in the FDCM – the Final Drive Control Module. The FDCM is a different component that apparently takes instructions from the cracked circuit board, but has the ability to override that board. When you have different electronic components that communicate with each other that is usually called a Distributed Control System. It is distributed because each module takes care of its own function so you don’t need one big computer running everything. So it appears the circuit board that might crack controls the 4WD Low and neutral and the FDCM transfers control to that module when that function is needed. I work with DCS systems, my guess is that the reprogramming of the FDCM added some diagnostics that check for signals from the board that controls 4WD Low and neutral. When the signals indicate the board might have the crack that initiated the recall, the FDCM prevents that board from ever taking control of the 4WD drive system. When you try to use 4WD low or neutral you get the only message that was available in the FDCM to display – “Service 4WD System”. This is a cheap patch that doesn’t fix the problem – a cracked circuit board that should be repaired or replaced. The internet is full of how to temporarily fix this problem. You open the hood, find the fuse box with the FDCM fuse, remove the fuse, start the vehicle and move it back and forth a few feet and turn off the engine. Then you replace the fuse and now you have 4WD control again – for a while. On my 2006 Jeep Grand Cherokee it is Fuse #25. The fact that many people are able to fix the problem with this fuse trick tells me that my circuit board is probably OK – or the warning message would come back immediately. I expect that the software patch that looks for a problem may be responding to intermittent noise instead of a solid indication of failure. Perhaps even electrical spikes from starting the engine or cycling the AC compressor might give a spike that the FDCM counts a failure and then locks out the 4WD control. With this kind of control systems they should be able to add a little more logic to not only detect conditions that indicate there might be a problem, but also do some testing to be sure that the problem is solid and not an intermittent. For example something as simple as putting time delays on the inputs to make sure that the indication of a bad board stays for more than a second or two. Or add some subsequent testing to make sure that the problem exists a few minutes later. And if it doesn’t, then reset the lockout. Jeep appears to be taking a big risk with the cheap fix. They admit to knowing they have a problem with a cracked circuit board. You don’t fix a cracked circuit board with software. They should fix or replace the circuit boards. We buy these vehicles because we expect some kind of quality from Jeep. As the word spreads that Jeep has screwed up the most desirable feature and is willing to cripple the vehicles rather than provide a real fix the word will get out and they will suffer like GM was over the problem with their ignition keys. Instead they are in DENIAL that this problem exists. From internet postings it appears to have become a CASH COW for less than reputable service departments. They deny that they’ve heard ANY complaints from people having this problem and proceed to try to sell new actuators or other fixes. The follow up posts often tell how they pay hundreds of dollars for fixes and then the problem comes back. These are growing and may soon hit a critical mass that could be severely damaging to the Jeep reputation. And heaven forbid that someone is killed or injured because they get caught in an off road situation and can’t get into 4WD low when they need it. Or someone who tows their Jeep behind an RV has to leave it in a bad location because it won’t go into 4WD Low and has it stolen or damages while they drive their RV to some place to get help. Chrysler Jeep needs to take responsibility for this screwed up fix and do a real N23 fix. Even if they have to spend a lot of money on circuit board replacement labor, it may be well worth it to protect the brand.

2 out of 2 people think this is helpful.

Your Answer

Add photo

Related Questions

Grand Cherokee
Looking for a Used Grand Cherokee in your area?
CarGurus has 53,270 nationwide Grand Cherokee listings starting at $995.

Search Jeep Grand Cherokee Questions

Jeep Grand Cherokee Experts

#1 Tom Demyan
Tom Demyan
Reputation 810
#2 tenspeed
Reputation 630
#3 thejeepdoctor
Reputation 580
View All

Related Models For Sale

Used Jeep Wrangler"
1,007 Great Deals out of 43,485 listings starting at $1,800
Used Ford Explorer"
1,180 Great Deals out of 48,321 listings starting at $800
Used Toyota 4Runner"
367 Great Deals out of 12,274 listings starting at $1,595
Used Jeep Liberty"
617 Great Deals out of 10,396 listings starting at $1,488
Used Chevrolet Tahoe"
1,081 Great Deals out of 33,344 listings starting at $2,995
Used Dodge Durango"
432 Great Deals out of 20,884 listings starting at $1,250
Used Dodge Charger"
817 Great Deals out of 31,517 listings starting at $2,950
Used BMW X5"
363 Great Deals out of 9,020 listings starting at $3,987
Used Ford F-150"
2,570 Great Deals out of 174,399 listings starting at $1,746
Used Jeep Commander"
122 Great Deals out of 2,432 listings starting at $4,995
Used Ford Escape"
1,710 Great Deals out of 56,182 listings starting at $1,400

Used Cars For Sale

2014 Jeep Grand Cherokee For Sale
256 Great Deals out of 12,363 listings starting at $21,994
2013 Jeep Grand Cherokee For Sale
107 Great Deals out of 1,228 listings starting at $20,625
2012 Jeep Grand Cherokee For Sale
211 Great Deals out of 3,226 listings starting at $15,597
2011 Jeep Grand Cherokee For Sale
294 Great Deals out of 3,774 listings starting at $15,274