Originally Posted by ColesburgTim
While on a trip last week in florida, I had the service 4wd system displayed. The 4 low switch was inoperative. I took to dealer yesterday after searching all posts associated with the display. Dealer found that almost every module flashed a DTC code at the exact same time. 30+ codes. They erased all the codes and display is gone & 4low works. They have no idea why it would throw that many codes at one time. Anybody ever seen anything like this?
There's a recall associated with this error - http://www.jeep.com/webselfservice/pdf/N23.pdf
I haven't had the recall performed yet, and I had the same error. I cleared the error codes by pulling a fuse to reset the final drive control module. The service 4wd system error went away and 4wd low started working again.
From another site:
Here's what I did:
1. Turned my Jeep on (engine running) checked that the 4wd service message was still occurring when I activated 4 LOW)
2. Turned my Jeep off and took the keys out. opened up the fuse box under the hood (the one closest to the cabin of the Jeep.
3. Located and took out the fuse labelled fdcm/ediff #33 or #25 ( in my case this was #25)
4.Shut the fuse box, closed the hood, got in my Jeep, started it with the fuse out put it in drive, drove about 20-30 feet forward then put it in reverse drove 20-30 feet backwards. (Be aware you will get the service 4wd light without pulling up the lever as you are driving)
5. Turned my Jeep off, keys out went to the fuse box put fuse back in, closed the fuse box and the hood.
6. Started my Jeep, activated the low 4wd switch and it worked!