how can i test rear right abs sensor ?

Hi
my tracs abs sensor comes on and i had my car pluged in at volvo and they saif that the rear right abs sensor is faulty how can i test this myself ?
Thanks
Richard 850R

its a 99% chance that its not the sensor but the abs module instead.

i don't know if the rear sensors are swappable but try this, if it is the sensor the code should tell you its the rear left instead!!

but my moneys on the module its a common problem a good dealer would of been able to tell you its the module instead.

[cootuk]

If it is the ABS module you can apparently get refurb ones rather than pay the dealer £££££

Sensors of this type are relatively simple to check. They create their own voltage (rising voltage) - and ideally they create approx 1.2 - 1.5 volts

Locate the sensor in question, and you'll find it has 2 wires coming out of it - you may have to find the 1st mutiplug in line - attach your multimeter to the wires, and in theory spin wheel and if sensor ok voltmeter (set to AC) will read 1.2 - 1.5 volts. But in practice you'll probably not be able to spin wheel fast enough to generate voltage (not a problem if testing front wheels!!)

Try rigging something to allow wires to stay attached at multiplug and feed into car, to multimeter, and go for a drive - I've done it before!!

So, look for 1.2 - 1.5 (a stady slightly lower voltage, say 1 volt, generally ok)

This test is same for any car which uses this sort of rising voltage sensor (eg, ABS, TDC sensors etc)

But I've also been reliably informed you can make your own DIY OBD rader, which some wire and resistor and LED............

[Chris_Rogers]

If you do a search on this forum you should find this subject covered before. With electrical values.
You can't read ABS codes on a '96 car without a Volvo scan tool.

Chris,

I thought OBD on 96 models was 'not quite OBD'......????

[warthog]

Hi,

According to Volvo diagnostic info, the wheel sensors should produce above 105mV ac when the wheel is rotated at 1 rev/sec. You are quite right in saying that the voltage will rise as the wheel rotates faster. In fact when the ABS system self tests (about 20mph) the wheels are rotating around 5 revs/sec.

Cheers

went to the dealer today, he found the right rear sensor faulty but from experience knew it was the abs module.

having it replaced under warranty from around £300.

i think everyone should get a warranty, try warranty direct, they agreed the repairs with no messing around. i only pay £200 a year so have saved £100 already!!!