ABS light comes on at 70 mph
 

Anyone know what could be causing the abs light to come on only when reaching 70 mph? If I drive below 70 mph, apparently indefinitely, the light will never come on, but if I reach 70 mph, the light triggers.

Pull the ABS code and it will tell you what going on and which wheel position. I have only known this to happen (personally) one other time and the owner had one tire (spare) that was a different size and when they reached XX mph it would trip off the sensor on that wheel.

Probably won't need to pull codes as I think you've just solved the problem. Front driver side tire is different size 215/40r17 and all the others are 215/45r17. Once I get tire replaced I should be good, hopefully.

Well its always good to have early resolve. The 40 tire would turn at 874 revolutions per mile and the 45 at 844 - 3% dif. There is probably enough error at 70mph to trigger the fault.;)