ABS light on when driving

[johhnnie]

Hi folks

Can anyone help me out with a wee problem , When i turn on the ignition the abs light flashes twice on the dash and then goes out ( manual says that is correct ) but just as soon as i start moving the car the light comes back on again , I have checked and cleaned all 4 sensors on the hubs and also the relay's just under the pump and cleaned up all the connections , You can hear the relays clicking when the ignition is turned on which leads me to believe they are working ok .


Anyone have any suggestions as its booked in for a MOT this saturday.

Its a 1991 mitsubishi gto twin turbo ( jap import )


Cheers

John

 

[Spark123]

It could be a failed wheel sensor. Not sure how easy it will be to get your car plugged into a diagnostics system, do you know anyone with electronics background who has an oscilloscope? It should be possible to connect to each sensor in turn to an oscilloscope with them still connected to the vehicle and see a waveform (usually a square wave) when the corresponding wheel is spun.

 

[Wontdothatagain]

I cant remember if they have floating or bolt on sensors. If they are floating they must be pushed right in against the exciter ring.

Near to the sensor there should be a conection plug, disconect it and with a multi meter check the resistance of the sensor, it should be about 0.20ohms.

If all of the above are ok, jack up each wheel and make sure you put a stand under the car. Disconnect the sensor and check the voltage coming from it with someone spinning the wheel. You must get the wheel spinning above 10-15mph as no voltage is prduced below this. You should get around 1.2-1.5v