ABS Testing

[Uncle Buck]

ABS light came on at the fall track day. Finally looking at it today.

I read on the web you can test the sensors with an ohm meter.

Anyone know what the reading should be?

They both seem to be reading open which I think suggests they are both bad but that doesn't seem likely.

Help!

[Ponyryd]

They may read open one way but will have a resistance reading the other, pretty sure they should be around .6-.8 ohms. Comparatively they should be the same, the actual reading doesn't matter so much as long as they're close.
If you're testing a Ford, my money would be on a broken tone wheel, sensors rarely fail, tone rings often do.

[Uncle Buck]

Tried them both directions still no joy fixing my abs light. Cleaned both front sensors just for the heck of it. Rings looked ok from what I could see. Maybe it's an issue with the rears.

[Ponyryd]

So you unplugged the sensors and checked the ends going to the sensors with an ohmmeter and it reads open? you must have two bad sensors then, they cannot work in an open state.
If you clear the code does it come back immediately? Or only after the car moves?

[Uncle Buck]

Both read open but seems unlikely both could go bad the same day. When I first start the car, the abs light stays on until the car moves then goes out. After about 5 mins of driving the light comes back on and stays on until the next restart.

[Ponyryd]

If it was an open sensor the light should be on immediately, I'm still leaning towards a tone wheel that has a crack in it. If it takes 5 min, go for a quick ride and do a panic stop before the light comes on, see if the abs actually works.