ABS Sensor Resistance

[GaSrAm]

After checking my sensors with a multimeter i find one with a high resistance reading and 3 with a reading around 10(00) ohms am i correct in thinking this could be the cause of my intermitant abs fault light ?

[sworks]

I can't remember the exact resistance (1000 - 1500 ohms?) but as long as the leads are the same length (can't remember if front / rears are different lengths) then you should get the same resistance

[GaSrAm]

Hmm .. well the 2 rear seem different to the front and they definatley had different readings , but the two fronts and a spare front i have all read the same as one rear . I ordered another rear sensor so at least i can eliminate that .

[HarryM1BYT]

The resistance of the leads will be in milli-Ohms, so any variation will be the resistance of the coil or the connections (if you are measuring at the ABS ECU). They should all measure the same within an Ohm or two.

[SD1too]

After checking my sensors with a multimeter i find one with a high resistance reading and 3 with a reading around 10(00) ohms ...
John,

MG Rover says that the sensors are active devices, therefore I don't think a resistance reading will be meaningful.

Simon.

[T-Cut]

The only way to test the performance of an ABS sensor is by the use of an oscilloscope. The resistance is not really relevant to its magnetic inductance.

TC

[GaSrAm]

They should all measure the same within an Ohm or two.

This is what i thought ,which leads me to believe the one that reads different could be broken

[FrenchMike]

After checking my sensors with a multimeter i find one with a high resistance reading and 3 with a reading around 10(00) ohms am i correct in thinking this could be the cause of my intermitant abs fault light ?

Hi,
not so simple:

6600


Mike

[HarryM1BYT]

As rightly pointed out, not so simple as I thought. I still stand by my comment that if the resistance is wildly different with the meter connected EXACTLY to same way - same polarity, then the sensor is most likely failed.

[Greeners]

try this..... (http://www.topbuzz.co.uk/maintenance/testing_abs/testing_abs.htm)

[GaSrAm]

Thanks for the info , i think the resistance test i did told me enough to suspect the sensor as 4 out of 5 sensors read almost the same and 1 reads totally different . I read that the sensor may produce enough voltage to pass the POST but then not supply enough to the ABS Modulator hence the intermitant fault , when the new sensor arrives no doubt i shall find out . Thanks again for all replies:)

as a side note i did not notice any polarity in the sensor as informed , they read the same either way they were connected

[GaSrAm]

just to update this issue , the n/s rear hub had surface rust on the face that the sensor reads .. after a quick polish the intermitant fault has disappeared , thanks for all the help

[SD1too]

An interesting outcome John. Thanks for letting us know.

Simon.

[HarryM1BYT]

Hi,
not so simple:

6600


Mike

Mike, if you get this, right at the bottom of the attachment it mentions the voltage step one at 0.5v the other at what looks like 3.0v (close to the bottom and not showing properly.

That is at odds with my findings of yesterday. The step is a difference between the two voltages of 1.0v. The actual voltage depends on the voltage across the battery, but stationary ignition on, I saw 9.39v and 10.40v. Se my recent ABS thread here...

http://www.the75andztclub.co.uk/forum/showthread.php?t=192924