we just had a severe winter storm in our area and had to switch into 4 wheel low to get over a few drifts. when i went back into 4 hi i got the message service 4 wheel drive come up on the (DIC) display, after reading a few posts from fellow H3 owners i got the simple fix to my problem. the 4 high button was stuck in. thanks hummer fourm and all the fellow hummer owners. saved me a trip to the dealer!