Volvo FM ABS

Hi all,

hoping somebody here can help, Volvo fm 8x2 tipper with 2 axles on abs has the light on the dash but no fault codes logged through the dash or on a diagnostic kit. When i run a test to see what sensor readings are given out its between 40-50km/h on both front ones and one rear one. but i unplugged the rear ones and the same speed reading was being given out. any help appreciated

Thanks In advance

Would guess broken wire somewhere although would have expected fault codes.

You can check sensor output with a multimeter, volt setting Iirc spin the wheel 1.5volts ish rings a bell, wheel needs to be spinning at a good speed, also worth doing a continiuty test on the wiring whilst you are in there.
Dirty or corroded pins on the wheel end connectors are a favourite this time of the year.

I would have thought that me sisconnecting the sensor at still getting a reading would have ruled out the sensor though? :smiley:

Is the light on the dash staying on after turning on the ignition or is it developing as a dynamic fault?

Seems to be staying on all the time

It will either be a bad sensor, wiring or the more unlikely ECU but there should definitely be a fault code if sensors telling you which one.

Without that I would go round and unplug each sensor at the wheel end and check the resistance of each with a multimeter. If they’re all ok I would suspect wiring next.

Something like this saves a lot of time over a multimeter checking everything is alright at the wheel end.

hgvdirect.co.uk/sensormaste … 0wod7_4J2g