THANK YOU. It was a coincidence from hell that brought me here. Two wires to the Transfer case computer were snagged by removing the back seat to replace the parking brake cable. Had to move the vehicle with the computer pulled . The light came on. Fixed the wires and reconnected thinking the broken wires were the problem. Still got the light. Was getting ready to check all the wires for continuity when I did a search and found you video. Thanks again.
The fix quit a day later. Took another look at both fuse boxes. The front box, fuse #22, FDCM Mod was blown. It is a 30 amp, "Jcase" fuse. Those other fuses just tell you what is happening, and this one does the work. One of the broken wires must have been grounded as it was being cut.
If you're constantly getting that message there's something wrong either wiring , slipping transfer case, or the actuator motors in the differentials have an issue as they often break the solder joints at their harness plug if they are cracking and loose they will trigger the 4wd . The front differential is rather fun to get the cover off if since the steering rack is right in the way . I never had issue with this service light even at 138k when my transfer case started to slip then at 145k it started I replaced the computer it shifted for two days but I noticed I had no axle diff lock up I replaced my failing case and still no low range and couldn't get the service message off with the fuse trick then I pulled the diff covers and found the front actuator motor harness plug was completely cracked off at the solder joint and the rear was loose . This failure of the actuator motor plug is common and probably the cause of many service 4wd message . Also once the transfer case control module sees enough failure it won't unlock with the fuse trick you'll need a good scan tool to clear it even after repairing the broken parts . I had put a new case in and new diff motors and still needed the tool to clear the tccm the fuse trick wasn't doing the job. . A cheap Bluetooth OBD2 reader like the blue driver will erase these codes it will also tell you the systems that the tccm has logged as failed which will tell you what is broken easier than hunting it yourself.
I've tried it three times this is the first time I've ever received that message my Jeep is a 2008 Grand Cherokee the message appeared two days ago I pulled a fuse I've done everything nothing works I've never had the first problem with this Jeep 145,000 MI
Yes you can use this method to reset the computer and get the system working as it should. Something in the computer needs resetting from time to time. I've done mine twice in the last year.
Did you get your issue fixed because that's the only way I can drive my Jeep to because it's stuck in 4low and the even autre part is I didn't even put it in for low it happened overnight while parked the next morning I came out to it to go to work and it was dead so I charge the battery and proceeded to start it and head off to go to work and it was in 4low and it would never come out since rendering it a gas hugging slow-moving rock that it's useless to me because I can't even afford to get it out in the hills to go 4-wheeling with it in the state it's in.
Mine usually lasts for around 12 months but it depends on how often 4x4 is used i think. The comment about soldered joints failing in the diff sounds plausible but I don't use 4x4 enough to warrant doing a more thorough investigation. This hack is good if you find yourself in a situation where you need it but it won't function.
