Hey guys im new to this forum! I have searched around here for an answer to my problem but cant seem to find anything so im hoping someone will be able to help me! I own a 2000 Mazda B3000 and I put a set of 31 inch tires on my truck. I just recently had a problem where my ABS light came on and my O/D light flashes and my Speedometer stopped reading.... so I went and changed the ABS speed sensor on my Rear differential and it got rid of the ABS light problem on my dash BUT the o/d light still flashes and my speedo doesn't work and the Tranny shifts really hard... cant find where he problem is at all! if anyone can steer me in the right direction that would be awesome!

 

Welcome to FTE.

A number of systems use & will be affected by the rear ABS speed sensors PID output to the computer, like the ABS, auto tranny, speed-o, cruise control come to mind. The computer needs to know that you've drastically changed tire size, as that's like changing the rear differential ratio, so if you didn't have the computer re-programmed for the tire size change, its programmed in shift points are being confused by the rear differential speed sensors uncalibrated/now corrupt PID input.

A Dealer, or good tire shop should be able to do the recalibration.

If that's been done, look to a wiring, or electrical connector/pin/socket problem between the computer & rear differential speed sensor.

Some thoughts for consideration, let us know how it goes.

 

If all 4 tires are the same size, it shouldn't be throwing a code. Even on a 4-wheel antiskid system with 4 individual wheel speed sensors, the pulse counts (rotation rates) for each speed sensor would appear the same to the processor on each input channel, so there shouldn't be a problem.

The only thing that would be affected is that your indicated (calculated) speed would be off versus your actual speed. I think you have a problem elsewhere, not caused by your tire swap.

That being said, the easiest way to start troubleshooting is to pull codes. The flashing O/D light indicates at least 1 transmission fault code is present. Get the codes and post 'em up here.