How common is wheel speed/abs sensor failure in 3rd gen t4r?

[xspsi6]

Just curious if this is a common problem with these as my speedometer is not working and has triggered all of the other associated lights and I will test them as soon as I find my multi meter leads :noidea:

 

[BlackWorksInc]

Just curious if this is a common problem with these as my speedometer is not working and has triggered all of the other associated lights and I will test them as soon as I find my multi meter leads :noidea:

A DMM will only get you so far as you really need to be able to test not only the frequency of the signal (something I don't believe Toyota has a specification for) but also the amplitude of the square wave which can be affected by dirt, debris, broken tone rings, damaged sensor, ect.

They don't seem to go bad too often, but that doesn't mean they can't fail. I would do the simple tests of voltage, continuity, and check connections; but really you can't test much more than that (you could see if the computer sees a signal from the sensor if you had a compatible scantool I suppose.) A member had made a thread about resistance being a possible way to test them (based on old vs. new part replacement they did) but without a large enough sample pool, it'd be more of a novelty.

 

[D Farms]

I got mud in mine and they stopped working, after I sprayed them out the problem went away

 

[xspsi6]

A DMM will only get you so far as you really need to be able to test not only the frequency of the signal (something I don't believe Toyota has a specification for) but also the amplitude of the square wave which can be affected by dirt, debris, broken tone rings, damaged sensor, ect.

They don't seem to go bad too often, but that doesn't mean they can't fail. I would do the simple tests of voltage, continuity, and check connections; but really you can't test much more than that (you could see if the computer sees a signal from the sensor if you had a compatible scantool I suppose.) A member had made a thread about resistance being a possible way to test them (based on old vs. new part replacement they did) but without a large enough sample pool, it'd be more of a novelty.

I did inspect all of the tone rings and connections and all were good visually also this is a FL truck so never seen mud or snow so underside has the bar codes still so the typical corrosion is not at fault here also our scan tool has a lab scope to check the square wave signals but of course this feature stopped working right when I need it most

I even checked the abs ecu and the connections and again nothing out of place but this an 01 so it has the skid control master/booster which I hope that is not my problem as that is pricey!

The only code I get is po500 which is vss however that would be all 4 wheel speed sensors not the out put shaft speed sensor on the trans and alldata has failed me on this one but without live data and a lab scope I am just stabbing at it in the dark, Do you know of any "hot fixes" or whatever the common fix/faults may be?