vs abs wheel sensors

[1997_vs]

Hey guys,
I've got a vs wagon and i have an abs fault code 31, which is right hand rear wheel speed sensor fault, just wondering what to do i.e is there a fix to it or should i just replace it? If it needs to be replaced where i can purchase a replacement and how hard it is to change?
Thanks
Mitch

[Brett_jjj]

Check the connectors and wiring to the sensor and if you find nothing out of the ordinary then replace the sensor.

[1997_vs]

Thanks Brett, would repco and those sorts of shops have the sensors? if i do need to replace it

[Brett_jjj]

I always try to use genuine holden with any sensors I replace,( or for any parts I replace for that matter),I have seen a couple of problems caused by cheaper aftermarket sensors but yes ,these places will have them or be able to get them for you.

[RX25SE]

ABS sensors are really only a A/C voltage generator and you can test this.
Jack up the wheel with the faulty sensor.
Grab a digital multimeter and set it to A/C volts. Disconnect the plug (ignition OFF) to the suspect sensor and connect the multimeter to the sensor.
Spin the wheel and check to multimeter for a reading. It will only read when the wheel is turning.

Does the ABS light come on? As soon as the ignition is switched on (stays on) or only once the car starts moving?

[ephect]

firstly, inspect the plug, prongs and wire as mentioned earlier, unplug and plug back in to ensure a good connection. then if all looks good clear your codes, and then check it again in a few days time.

the abs sensor is incased in the hub itself, if its faulty you have to change the hub as well

wont hurt to test as RX25SE has mentioned to narrow it down.

[RX25SE]

the abs sensor is incased in the hub itself, if its faulty you have to change the hub as well

I think the OP mentioned it was RH rear. Being a wagon this means the sensor is mounted in the axle tube.

Maybe pull out the sensor and make sure its not covered in metal particles as they are a weak magnet.

[ephect]

ahh crap missed that.. still inspect and compare it with the other side and ensure the splines/cut outs are still fine both sides, another good test is swapping left and right sensors clear your codes and it should log LH rear fault. Or purchase a set from holden.

[wortus]

ABS sensors are really only a A/C voltage generator and you can test this.
Jack up the wheel with the faulty sensor.
Grab a digital multimeter and set it to A/C volts. Disconnect the plug (ignition OFF) to the suspect sensor and connect the multimeter to the sensor.
Spin the wheel and check to multimeter for a reading. It will only read when the wheel is turning.

Does the ABS light come on? As soon as the ignition is switched on (stays on) or only once the car starts moving?

I'd suggest using a CRO if you have access to one and comparing the actual waveform output to one ou know works. I'd think the output is more a square wave than a sine wave and would to some extent change in peak voltage with speed as well as frequency.

[1997_vs]

Initially after starting its not on but shortly after moving it comes on. I'll pull out the sensor on the weekend and have a look at the left side one as well and see if anything looks out of the ordinary then go from there. Thanks guys

[moose man]

I'd suggest using a CRO if you have access to one and comparing the actual waveform output to one ou know works. I'd think the output is more a square wave than a sine wave and would to some extent change in peak voltage with speed as well as frequency.

Yep, oscilloscopeis the only way to check a wheel speed sensor. Impossible to see a smooth consistant wave on a multimeter.
Wave should have round peaks, not square. Voltage peaks do not matter, it's the wave frequency that the computer compares.

[RX25SE]

I agree, an oscilloscope is best.
Multimeter was just to check for any output, as this is a quick and easy test that most people could do.

[Hugo92]

probs a stupid question but i got my first car 97 commodore station wagon and i checked the fuses it doesn't have any of the fuses for ABS was the Abs a stock feature when it was released or was it an after market accessory? just wondering :P

[hako]

It was an option so not all VS vehicles had it fitted. The ABS unit is mounted rearwards of the battery towards the driver and is a aluminium box about 150X100 and has brake lines going to it - if it's there you cannot miss it.

[Brett_jjj]

Yep,ABS was still an option on the VS.My VS sedan doesnt have it (thank god).I did however, get a drivers side airbag and cruise control on it..