You can test for electrical continuity through the sensor. You can do it from the abs ecu. For how to do it can I suggest that you have a look at www.frenchcarforum.co.uk and do a forum search with MJM as the author. I asked the same question on there about 2 weeks ago and received good advice.
MJM
M J May
September 2009
no self test you need diagnostic equipment to ckeck this fault
ih
July 2009
I can answer this question...
how to test the abs wheel sensors for faults (citroen xantia vsx estate)?
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