the only way to read the fault codes in your system is to take it to the dealer. They have to connect directly to the EBCM for diagnosis. It'* usually about 80 bucks shop time just to check for codes.
The EBCM will run you about 100 bucks from a wrecker (4 or 5 hundred from the dealer, about half that from the web), the PMV will run you about 900 installed. Unless you wanna tackle it yourself, then you can get one from the wrecker for about 200. It'* a bitch. I've done two of them now. If it'* a wheel speed sensor, you can buy the rears for about 50 bucks each, but the fronts are embedded in the Hub/bearing assembly.
See how expensive? You need to get it scanned. No shotgunning on this system.
Short of that, go in and check the connections to the PMV (under your airbox), EBCM (on the firewall, right above the 'hump' between the footwells) and all 4 wheel speed sensor harnesses on the backs of the hubs.