Galaxy ABS sensor

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Sat 26 May 2007 23:19
Galaxy ABS sensor - dave2
The abs light is on and a unipart computer says its a front sensor.
Ive tested both front sensors which both give a voltage reading when the wheel is turned but only one shows a resistance of just over 1000 ohms.
The other shows zero.

I cant understand why, if theres no resistance how it can still give a voltage reading of approx 0.4v.

Does anyone know how to remove the sensors without having to smash and drill it out, as its a plastic moulding fitted into a deep rusty casting.

Will the light go out if replaced or do I have to have the codes cleared by the dealer.

Thanks

Dave

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Sun 27 May 2007 01:05
Galaxy ABS sensor - Screwloose
Dave

How about a year; there have been quite a few different ABS set ups around in the Galaxy era. Most will reset the light after a clear self-test; but the code will remain.

What use is this Unipart computer if it can't tell you which side has registered the fault code? Wheel speed sensor codes are always handed.

The sensors will be rusted in and will need lethal force to remove them. Refitting is not an option.
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Sun 27 May 2007 08:43
Galaxy ABS sensor - jc2
VW parts again.
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Sun 27 May 2007 14:24
Galaxy ABS sensor - dave2
Sorry, it is a 1999 TDI Zetec and the computer did indicate that the offside senor was at fault. Which is the one that shows no resistance reading, although when turned gives a voltage reading. Im a little concerned that if its got a open circuit how can it generate a voltage ?
These sensors a expensive so I want to be sure before buying.
Does anyone know where they can be bought cheaper as Ford want £70 for one.

Thanks Dave
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Sun 27 May 2007 16:57
Galaxy ABS sensor - Aprilia
Is it showing open circuit (i.e. infinite resistance - like a broken wire) or is it showing a short circuit (zero resistance)?

I believe that like most ABS sensors these are actually variable reluctance pickups - i.e. the system acts like a little electrical generator and generates an approx sinusoidal voltage signal as the wheel is spun.

If the sensor is disconnected from the ECU then it is possible that your voltmeter's input impedance is so high that even a faulty sensor could cause a voltage to be recorded. Once connected to the load of the ECU's input circuitry that voltage would be very low, causing the fault to be flagged.

If the sensor is recording either a short- or open- circuit then it is faulty.
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Sun 27 May 2007 17:42
Galaxy ABS sensor - Screwloose
Dave

This is likely to be a Teves Mk20 IE system on that year. The resistance on any one of its sensors should be 1000-1300 ohms.

Getting a voltage reading on an open-circuit sensor does seem odd; but the systems self-test at key-on will instantly pick up an incorrect resistance and flag 00285.

£70 isn't too bad for a wheel sensor [I've seen a £300 one;] shop around the various Shalraxy suppliers [GSF etc] and you may find one cheaper.
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Thu 31 May 2007 00:16
Galaxy ABS sensor - dave2
Thanks everyone for your advice,It does all add up to be the sensor so I'll be looking for a replacement.

Thanks again
Dave
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