I have a 2000 Ford Explorer Sport, and the 4wd and 4wd low lights flash about six times, the ABS light is on, as well as the chech engine light. I just got back from a local shop I trust that could scan all of the codes in my explorer. It came up with a c1230 & c1102 for the ABS, which sounds like the speed sensor on top of the rear differential. The check engine light is because of po171 (system too lean bank 1) and po174 (system too lean bank 2). And they told me the "shop computer" could not communicate with the 4x4 module. Has anyone heard of this? They told me it 'might' be a bad 4x4 module, which was around $400, but my 4x4 and 4x4 low range work fine, but the lights on the dash (4wd & 4wd low) flash, and do not indicate the mode the 4wd is in. Again, the 4wd functions fine. Any suggestions? Thanks in advance!