How do you check an ABS sensor?

d4v1d sm4rt

A2OC Donor
I have the ABS light, the traction light and the red braking symbol on and there is a fault code that says right front abs fault. I have tried to measure the sensor and there is no resistance value or continuity so I thought it was faulty, however when I checked the other side it was the same.
I then measured the voltage whilst the wheel was being rotated and that didn't show anything on either side.
Baffled... :confused:
 
I have a scanner that has given a code but there is no way definitively to identify whether it is the sensor or maybe the loom?
 
You are checking the sensors on the spindle, right? The bearings on the A2 are magnetic and this is what the sensor sees. I think you could swap the sensors, left and right and see if the problem moves with the sensor. I had to replace one of mine when I changed bearing. Got a knock off one from eBay quite cheap.
 
Yes that is good logic but unfortunately they are corroded solid in the hub and the only way to remove them would be to destroy them and drill out the hole. Also the sensors are handed and the top kicks back on each side to avoid the disc so it may not fit. I did also clean the face of the bearing to no avail. Have a sensor on order from e bay ( £7.99 ) but it is the left side so will have to think of a way to make it fit. Allparts wanted £34 and Euro car parts wanted £41!
The bottom of the sensor has a flat tab on it and I am wondering if that is handed in its proximity to the bearing? So if fitted the wrong way round it may not work.
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Using your logic I took one off of a car that I recently replaced that I knew would come out OK and it worked! Yay!
I did have to drill out the old one unfortunately. It struck me when I looked at the design that the main shaft of the sensor has smaller ridged sections that are just right for rust to grow onto and seize the sensor hence why they always seize up. Needless to say the new one is well greased.
 
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