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Discussion Starter #1
So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
 

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Unfortunately, I do not have much in the way of suggestions.....but I thought it was prudent to state that (at least as far as I am aware, please someone correct me if I am wrong) there have never been any WK2's that had both a selectable 4Low transfer case and rear wheel drive only (2WD). I do believe that if you have a 4WD WK2, then it's all time 4WD. I only bring it up so there hopefully won't be any confusion for people who may try to help you but might not come forward due to confusion with the vehicle description.

Also..... how do you know the transfer case is, in fact, still in 4Low? It seems you mention the 4Low light is not illuminated.
 

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So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
Welcome to the Forum, from Cave Creek AZ.
 

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2014 Summit 5.7 4wd 20" tires swapped to 18", added all skid plates
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My GUESS is that there is a shift motor which isn't working right. If it's like other shift motors I'm familiar with it includes a status circuit that tells the computer where it's at rotationally. Sometimes that part gets mixed up and the computer doesn't know what position the motor is in so it stops doing what you want it to do. Based on what you have done I would see if I could see such a motor sticking out and if it's removable I'd first gently bang it with a hammer and see if that fixes it. If not I'd pull it out, wiggle/rotate the shaft back and forth slightly and try to end where I started then put it back in and see what happens.
 

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Discussion Starter #5
Unfortunately, I do not have much in the way of suggestions.....but I thought it was prudent to state that (at least as far as I am aware, please someone correct me if I am wrong) there have never been any WK2's that had both a selectable 4Low transfer case and rear wheel drive only (2WD). I do believe that if you have a 4WD WK2, then it's all time 4WD. I only bring it up so there hopefully won't be any confusion for people who may try to help you but might not come forward due to confusion with the vehicle description.

Also..... how do you know the transfer case is, in fact, still in 4Low? It seems you mention the 4Low light is not illuminated.
Hey, thank you for pointing that out, Thunderspud. It is, in fact, full-time 4WD unless I put it in 4WD LOW. I say that I know it is in 4WD LOW by driving it.
 

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Discussion Starter #7
My GUESS is that there is a shift motor which isn't working right. If it's like other shift motors I'm familiar with it includes a status circuit that tells the computer where it's at rotationally. Sometimes that part gets mixed up and the computer doesn't know what position the motor is in so it stops doing what you want it to do. Based on what you have done I would see if I could see such a motor sticking out and if it's removable I'd first gently bang it with a hammer and see if that fixes it. If not I'd pull it out, wiggle/rotate the shaft back and forth slightly and try to end where I started then put it back in and see what happens.
Thank you, JimnTempe
 

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Hey, thank you for pointing that out, Thunderspud. It is, in fact, full-time 4WD unless I put it in 4WD LOW. I say that I know it is in 4WD LOW by driving it.
Yeah, 4Low should be pretty obvious I suppose, lol. Mine pulls like crazy. I just wanted to make sure since you mentioned 2WD that you might have another model year or another model.

I agree with what Jimintempe posted earlier. My guess is it's the transfer case motor. While sitting in neutral, foot on the brake, can you hear the transfer case mechanically attempting to engage/disengage 4Low when pushing the button? I had an issue with the rear transfer case seal a while back that was either a consequence of or resulted in a failed rear driveshaft. The tech at Jeep mentioned in passing that he had seen at least a couple cases where the failure of that rear transfer case output seal would leak fluid onto the motor that engages/disengages 4Low on the transfer case and cause it to malfunction. Luckily mine didn't get to that point, but it's worth mentioning. I can't tell from your description of already performed actions if you checked that motor or not. If that is what you're referring to by the transfer case module, then I'm all out of ideas currently.

FWIW, assuming you have the same MP3023 transfer case I do, I think the Mopar part number for that motor is 68071235ac. Here it is at RockAuto unless the link gets blocked.....

 

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Discussion Starter #9
Yeah, 4Low should be pretty obvious I suppose, lol. Mine pulls like crazy. I just wanted to make sure since you mentioned 2WD that you might have another model year or another model.

I agree with what Jimintempe posted earlier. My guess is it's the transfer case motor. While sitting in neutral, foot on the brake, can you hear the transfer case mechanically attempting to engage/disengage 4Low when pushing the button? I had an issue with the rear transfer case seal a while back that was either a consequence of or resulted in a failed rear driveshaft. The tech at Jeep mentioned in passing that he had seen at least a couple cases where the failure of that rear transfer case output seal would leak fluid onto the motor that engages/disengages 4Low on the transfer case and cause it to malfunction. Luckily mine didn't get to that point, but it's worth mentioning. I can't tell from your description of already performed actions if you checked that motor or not. If that is what you're referring to by the transfer case module, then I'm all out of ideas currently.

FWIW, assuming you have the same MP3023 transfer case I do, I think the Mopar part number for that motor is 68071235ac. Here it is at RockAuto unless the link gets blocked.....

So, to start, Thank you for your insight here. Well, pushing the 4WD LOW button does nothing. There is no attempting to engage/disengage. It's in 4WD Low, period...haha. But, thank you for bringing up the motor, I haven't performed anything mechanical, yet. The transfer case module is an electronic unit positioned in the hideaway underneath the floor directly beneath the driver's seat. Easy to access, and I read where this solved a lot of other's issue like mine. Shame that I spent $275 on a new module and it didn't work. Lastly, thanks for the link. I'll definitely keep that in mind. I just know when I take it to a dealer, I am going to be asking a lot of questions when they come back with a diagnosis. It wouldn't surprise me one bit if they come back saying it the transfer case itself, but they better have performed a lot of troubleshooting to prove that. Thank you, Thunderspud! A lot!
 

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Discussion Starter #10
So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
I want to add a picture I took of the instrument panel. The 4WD LOCK warning light I spoke of earlier; I cannot find any information about this either in my owner's manual or on the web. Does anyone have any insight as to what this light is for or relates to? Maybe it's a light letting me know what my current condition is: I'm stuck in 4WD (Low). LOL.
229356
 

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I've have QD2 and cannot replicate 4WD LOCK in any of the modes. Only get the 4WD LOW light when I have it in 4WD LOW. The Owner Manual has no mention of 4WD LOCK, yet we apparently have that Instrument Cluster light. From what I've read, it appears to light after 4WD Low usage and it does not fully disengage when you press the 4WD Low button to disengage. Have you checked to see if there is fluid in your TC?
Try reaching out to the poster below. He had the exact same issue 3 months ago. Likely resolved by now.
 

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What I have read on the MP3023, it doesn't explain exactly how it shifts, but it only has a single shift motor and an index transducer.

I know for a fact, because the description says it, the motor turns a gear that has cam, lever, inclined plane and ball to increase and decrease pressure on clutch pack. What it does not specifically say, but you can see clearly on the same shaft as the gear for the clutch pack is a shift fork that would shift the gear from direct, to 4WD LOW and then into neutral. There is a sensor that looks to plug into the teeth of gear wheel turn by the motor, that is sense the index of the gear. Also when you shift into 4WD LOW, you have max pressure on the clutch pack, virtually locking it in Part Time 4WD.

So, it only makes sense the single motor adjust pressures on the clutch pack and then drives one extreme or the other before it grabs the shift fork to shift into 4WD LOW or Neutral.

There is a pump, but best I can tell, all actuations come from motor, gears and linkages, nothing hydraulically activated, the pump is just there to circulate fluid. It can't hurt to check fluid level, but I doubt low fluid would cause the system to fail to shit, perhaps lack of lubrication might cause it to hang up. I have confirmed myself, if you're low fluid it will cause the clutch pack to act roughly when the trans shifts and impulses are put on the driveline. So fluid in the clutch pack is part of its smooth operation.

When you try to shift out of 4WD LOW, do you get the message in the instrument panel instructing you how to do it? And do you read and follow it? This might help narrow down the problem. If you've met all the conditions to shift the XFR Case, but are still getting the message explaining what you have to do to shift, then the computers are for some reason concluding you're not in neutral, less than 3 mph, etc then it will prevent you from shifting and giving you the message about how to shift. If you're not getting the message and meet the conditions, then something has broken and its not shifting. I would think you would get Service 4WD warning if you had a bad motor or sensors.
 

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Discussion Starter #13
What I have read on the MP3023, it doesn't explain exactly how it shifts, but it only has a single shift motor and an index transducer.

I know for a fact, because the description says it, the motor turns a gear that has cam, lever, inclined plane and ball to increase and decrease pressure on clutch pack. What it does not specifically say, but you can see clearly on the same shaft as the gear for the clutch pack is a shift fork that would shift the gear from direct, to 4WD LOW and then into neutral. There is a sensor that looks to plug into the teeth of gear wheel turn by the motor, that is sense the index of the gear. Also when you shift into 4WD LOW, you have max pressure on the clutch pack, virtually locking it in Part Time 4WD.

So, it only makes sense the single motor adjust pressures on the clutch pack and then drives one extreme or the other before it grabs the shift fork to shift into 4WD LOW or Neutral.

There is a pump, but best I can tell, all actuations come from motor, gears and linkages, nothing hydraulically activated, the pump is just there to circulate fluid. It can't hurt to check fluid level, but I doubt low fluid would cause the system to fail to shit, perhaps lack of lubrication might cause it to hang up. I have confirmed myself, if you're low fluid it will cause the clutch pack to act roughly when the trans shifts and impulses are put on the driveline. So fluid in the clutch pack is part of its smooth operation.

When you try to shift out of 4WD LOW, do you get the message in the instrument panel instructing you how to do it? And do you read and follow it? This might help narrow down the problem. If you've met all the conditions to shift the XFR Case, but are still getting the message explaining what you have to do to shift, then the computers are for some reason concluding you're not in neutral, less than 3 mph, etc then it will prevent you from shifting and giving you the message about how to shift. If you're not getting the message and meet the conditions, then something has broken and its not shifting. I would think you would get Service 4WD warning if you had a bad motor or sensors.
So, I don't get the instructions on the Instrument Panel. I starting to lean towards the XFer Case Motor or the XFer Case itself. I'm taking it to a recommended XMSN Place tomorrow. I'll know in the next couple of days. It just depends on how busy they are. Thanks for all of your help!
 

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So, I don't get the instructions on the Instrument Panel. I starting to lean towards the XFer Case Motor or the XFer Case itself. I'm taking it to a recommended XMSN Place tomorrow. I'll know in the next couple of days. It just depends on how busy they are. Thanks for all of your help!
You need to have the engine running, transmission in Neutral, and vehicle speed between 0-3mph. Preferable rolling slowly. If you try to shift the XFR Case without being in these conditions, the XFR Case won't shift and you'll get a message on the instrument panel instructing you how to shift the XFR Case properly.

Have you've getting these instructions and have you've been following them?
 

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Discussion Starter #15
Yeah, I did all of that numerous times, but pushing the 4WD Low button does nothing as it should release the transfer case back into full-time 4WD at that point. The Jeep is in the shop now. I'll make sure to post what is found out so hopefully others can have a more successful troubleshooting journey.
 

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My 2014 QD2 shows "4x4 Low" You also have a check engine light, do you have a code reader, i'm guessing that would also shed some light on what's going on.
 

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So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
This same thing just happened to me. 2014 Jeep GC limited. Service 4whl light came on and veh seemed like it was in 4whl low. I did the transfer case Neutral procedure and there was a very loud bang. Then I could not switch to the various drive modes. I subsequently took it to my trusted mechanic. He replaced the transfer case motor and TC motor control. It now works great. He said this is becoming common in the WK2. Im hoping for a recall. This was still a $1,000 repair but cheaper than a new TC.
 

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Had this issue about a month ago. I had never changed the battery. The garage I took it took it to said they could find no codes, nor did they have any issues after test driving 3-4 times a day over 4 days. I told them to fo go ahead and replace the battery and not an problem since.
 

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So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
In my case it was a faulty transfer case control module which took FCA (Australia) 6 weeks to source due to lack of spares in country. Apparently the electric motor is cheap and nasty and prone to failure. To me it smacks of poor design where a module failure can incapacitate the vehicle.

John
 

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So, recently I started getting the 'Service Four Wheel Drive System' warning message intermittently. Well, in my infinite wisdom, I wanted to check if the 4WD system was still operational. Wrong decision. I put it in 4WD Low, drove 40-50 feet, and attempted to return the transmission to 2WD, but with no luck. The system is definitely in 4WD Low. The console 4WD switches are currently as such: 4WD LOW button light=OFF, 4WD Selector=Auto light ON, Neutral button light=OFF. The XMSN is still in 4WD LOW.

So far, I have performed the following troubleshooting:
1. Disconnecting the battery for 30 mins - several hours - No luck
2. Removed, inspected, and reinstalled Fuse F94, 10 amp red, Shifter / Transfer Module - No luck, but now I have a Check Engine Light and 4WD LOCK warning light
3. Removed the transfer case module unit from underneath the driver's seat. I inspected the connectors for corrosion (None), reseated the connector. - No luck
4. Removed and replaced transfer case module unit with a new unit - No luck
5. I have performed the prescribed shifting directions from the Owners Manual to attempt to shift back into 2WD.

My next step is to tow it to a local dealer for troubleshooting. I may have it done tomorrow, so if anyone reads this and has any additional advice or insight, I would appreciate the help. Thank you, all.

- Chris
 
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