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Hi All

I am new to this forum, however have used the forum as a lurker on prior occassions and understand how valuable it is to share information.

With that said i wanted to bring up the issue of the whole "Service 4WD System" alert code we get on the console of the commander.

First let me say i have a blue 5.7l Hemi Commander.

The code popped up and sure enough i admit i have been delinquent in serving my differentials and transfer case.

So first step was to do exactly that and change oil on all three expecting to see the service alert go away. No such luck.

As others have found despite having the ability to read OBD2 codes with my code reader you cannot read these codes or status.

So i conceded to go to my local dealer and pay to get the code. Yes i too came across the service bulletin from way back saying the module potentially needed flashing and that it was possibly and erroneous code but.....my background from way back is electronics and it made me suspicious as to why the code would even get flagged to appear if it was erroneous and only do so after i have had the vehicle all these years.

Dealer read my code and my instructions were to reset the code but it popped up again and remained active.

Thats a heads up to something more than erroneous code.

The code i got in my case was C1417.

So i pulled the diagnostic sheet from my electronic factory service manual.

It provides a step by step sequence to fault finding which pretty much anyone can follow using a test lamp and multimeter.

Yes there is a part where it looks to use the Scantool system to activate things but with a bit of logic one can fathom out where the issue really lies.

The thing that has me concerned is that many of the posts i have come across on the web related to diagnostic popping up on any Jeep have had people forget about it if it goes away.

So here is my concern that i would like to obtain clarrification about from someone in the know on these things. NOte i am not a mechanic. This is DIY for me. Simply because i do not trust the dealers since its been my experience even with my lay knowledge i tend to know more than them about my vehicle. They dont seem to read whats in the service manual.

On the differentials both front and rear there are solenoids.

According to the wording on the diagnostic sheet it says and i quote,

"When Monitored:

The solenoid is active, no solenoid supply circuit DTCs are present and battery voltage is normal".

Set Condition:

The FDCM detects the Front Differential Solenoid Control is shorted low.


So my big question is ....

Does this mean that in normal drive mode which is continuous 4WD the solenoids are always activated.

If so then my point is that in the event people do not deal with this code when it pops up the question arises at to what state the differential is running in and how safe that is.

Ie it is then my understanding (I am assuming i do not know) that the differential would be in neutral with the solenoid not active.?

Is this the case. Which implies that were this to happen to the rear one would have no drive at all.

From what i can ascertain the activation of the T lever when the vehicle transmission is placed in neural merely activates the solenoid in the transfer case changing the vehicle from 4WD high to 4WD low.

The solenoids in the differential are serving the same function therefore as the 4WD vehicles that have the external mechanicl diff lock and merely engaging the differential.

In my case thus far i have determined that the fault is real and that the fault lies in output from the FDCM not being present.

The other question i then have is what are the consequences if any to driving the vehicle without the fault being fixed.?

Alternatively one could interpret the statement that the solenoid is active as being that its only made active when its monitored but then when would this occur only at start up.

From my previous electronic experience it would make sense to have the solenoid operate in an active state normally so that when it does not a fault condition can be established. This would also be a kind of fail safe fault condition.

Can anyone shed detailed light on the operation involved here also exactly where the FDCM is that provides the output to activate the solenoids. I have found two conflicting locations. One under the second row seats and the other right in front of the fuse panel under the hood next to the battery.

Thanks the search continues.

ROb
 

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My jeep is currently at the dealership for c1417 error. So far they have replaced the FDCM which in turn has caused a lot more codes to pop up I guess.

When I went wheeling with my QD2 system with the c1417 error code active, my 4wd still worked, but my front diff did not lock.

That is about all I can offer, until I get my jeep back then I might have some more info on what they did to fix it..
 

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I jumped through hoop after hoop, got diagnosis after diagnosis, got update after update to the computer...

Check your fuses guys.

1 little blue #15 fuse (under the hood) fixed EVERYTHING!

Had "service 4wd system" message, had traction control light on, ESP light, brake lights not functioning properly...

Go to autozone, buy their little fused tester kit for $12 bucks (comes with a few fuses), use your manual to locate the associated fuse and just check it.

After you do this, report back here to let us know whether or not if resolved your issue or not. Good luck.
 

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Which 4wd system is this happening on? My 09 Hemi has the "open diffs" no E-slip and a Chryco 8.25 rear axle, I guess that's the QT2 system.

I'm guessing your having this issue on the QD2 system?
 

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I have the same issue on my 06 Hemi Commander. So far I came up with the following. on Start-up the FDCM checks the resistance on the diff solenoids. they need to be 13.5ohms. If they are not you will get teh service 4wd error. What I am going to do weekend is make a 13.5 ohm resistor and connect it to the wiring harness of the diffs and see if my error goes away.
 

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I also get this error once in a wile when I am on the road after a wile it goes away so I have been ignoring it, I will try and check the fuses when I get a chance but if anyone does it before me please let us know, I am pretty sure I will take a wile to check.
 

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Yeah if you remember which fuse it was that would really help.
It is a blue fuse (a number 15), you need to look in your manual and locate it (or check online for how to locate it), it is the fuse associate with your brake system, or maybe 4x4 system.... I will try to take a peak at mine asap and do what I can to help narrow down the one I replaced in mine.

It fixed a number of problems I was having including the "service 4wd system" messages...

I will try to get more info, but looking in your manuals, familiarizing your self with the fuse box (the ones under the hood), is a good start...

CHECK THOSE FUSES!!!!
 

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So, initially my issue was that the traction control symbol and ESP/BAS icons were intermittently showing up on my dash with the "service 4wd system" message. Brought it back to the dealership, they flashed the ABS module and said everything was good to go. Get back home (dealer is an hour away) and my dash lights back up again like a Christmas tree. A few days later I came to find that my break lights were not working at all (none of them).

I started to do some research and thought that replacing the brake switch (located directly behind the brake pedle) might resolve the issue. ("Brake switch half stuck" was one of the codes my mechanic originally pulled when he scanned the computer).

$14 dollar part, very simple job. So I replaced the brake switch and the issues still persisted.

Did a bit more research, drove down to autozone, bought one of there little fuse tester kits for $12 (came with a few fuses in the kit), located the blue fuse above, tested it with the tester........................ DEAD FUSE!!!

Put the new one in and BINGO! All issues stated above resolved 100%.

All I can say is, familiarize yourself with the fuse box, figure out which fuses might be associated with your issue and check any or all of them. A dead fuse is a problem.

Im far from a mechanic but apparently have more common sense than all of the boneheads that were paid to "fix" my problem.

I really hope this can help someone. Also, once you open your fuse box, there is a diagram on the reverse side of the lid clearly showing which fuse is associated with what (heating, wipers, brake light, AC...)

Good luck guys!


 

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So, no one answered my question yet! Is this with QD2 or QT2 or both? I have the rare Hemi with QT2, just wondering if need to be on the lookout for this issue.
 

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Thank you Dirty this makes the job much easier I will try this and hope for the best. Thank you again!!
 

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Thank you Dirty this makes the job much easier I will try this and hope for the best. Thank you again!!
You never really know. Could be a relay or something else extremely minor in your case. Who knows... Could be major... Good luck though and try to post the results up when you do fix your issue, just to help others down the line.
 

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i recently purchased an 06 limited 4.7l with qd2. after 5 days my wife says she is randomly getting the traction control, esp, bas light with a clunking sound from the transmission area. no service four wheel drive message. the lights go off after the vehicle is turned off and restarted but have returned every time she has driven it. i purchased the vehicle from a toyota dealership and have a 6000 mile powertrain warranty, but i think it is probably electrical and the dealership is 3 hours away and i think it would be a waste of time. i am also out of town so i haven't been able to observe it myself. any advice on where to start when i get home would be greatly appreciated.
 

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This may not be related but we went to Colorado and Moab this summer and everything worked great. The next day after returning to low altitude, I got the dreaded message. no other lights, just the message. I scheduled to have the dealer fix it and sure enough the message had disappeared the day before they picked it up. They said it needed a new solenoid and replace it.

I still wonder to this day if the sensor might be influenced by the environment and have mildly questioned whether the solenoid needed to be replaced. It has run great ever since. FYI - 2010 hemi with QDII.
 

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i recently purchased an 06 limited 4.7l with qd2. after 5 days my wife says she is randomly getting the traction control, esp, bas light with a clunking sound from the transmission area. no service four wheel drive message. the lights go off after the vehicle is turned off and restarted but have returned every time she has driven it. i purchased the vehicle from a toyota dealership and have a 6000 mile powertrain warranty, but i think it is probably electrical and the dealership is 3 hours away and i think it would be a waste of time. i am also out of town so i haven't been able to observe it myself. any advice on where to start when i get home would be greatly appreciated.
Read my post at the top of this (2nd) page.
 

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So, no one answered my question yet! Is this with QD2 or QT2 or both? I have the rare Hemi with QT2, just wondering if need to be on the lookout for this issue.
The issue the OP describes is for the QD2.
 

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So, initially my issue was that the traction control symbol and ESP/BAS icons were intermittently showing up on my dash with the "service 4wd system" message. Brought it back to the dealership, they flashed the ABS module and said everything was good to go. Get back home (dealer is an hour away) and my dash lights back up again like a Christmas tree. A few days later I came to find that my break lights were not working at all (none of them).

.....
This is a great write up for those who have multiple electrical issues at the same time, just like Dirty. However, for those who only get the Service 4WD message, it is less likely to be the fuse. It's always worth checking, though.
 

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I thought I'd share my experience with this...

All I had was the Service 4WD message (C1417) in the EVIC. It was not always present, and I could usually clear it by cycling the key in the ignition. I was always able to shift into 4-lo without issue. I drove around with this for years.

So this past Monday I was at the dealership having the front differential serviced for a leaky seal, and had a chat with the tech about the C1417 code. He recommended replacing the solenoid AND harness. Since everything was apart anyway, I said to go ahead. Long story short - problem solved. He said the harness wasn't looking too fresh.

The 4WD system is complex, and a short anywhere can give you a generic message in the EVIC. The C1417 code should at least localize the problem to the front differential.
 
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