General abs and spedo problem

[snowdog]

hi

For my first question my daughters car has the abs light on all the time and the spedo is reading lower than actual speed ie:-reading 20 doing about 35
could this be connected.

1.2 mk2 Punto elx

 

[Noddy]

As ABS systems dont work at low speeds they look at the speed sensor output and if its below say 5mph then the system wont activate even if the wheels are locked up. If the speedo is reading incorectly then im guessing this is caused by the speed sensor giving an incorrect/intermittent signal to the Speedo and causing problems with the ABS as well.