Two months ago the abs and e-brake came on and the speed-o stopped working, a week late the check engine light came on. Had codes pulled and was said to be speed sensor. Replaced the one on the rear end and that eventually fixed the speed-o and the engine light but not abs and brake light. Now 2 months later engine light back on no speed-o and now no odomoter either. Code pulled from AZ was a po501 (speed senser "a") Had a shop run some codes and found that pcm is showing 245 70 20 tires and I have 275 70 20. They also said that the front and rear diff are not jiving. The front axle came up at 34mph parked while the rear was at zero like it should. could this just be my front abs speed sensors or the worst scenario being the pcm? Any input would be appreciated.