For the last three years my V70 AWD has intermittently had the ABS/Trac warning indicator lighting up. Recently it is on most - but not all - of the time.

A volvo dealer says there is a 'permanent' error code on the O/S rear wheel rotation sensor (although the problem is only intermittent). They suggest fitting new rotation sensors (about £250) and if this doesn't work I may need a new ECU (£400+).

This seems a bit heavy duty. Is there anyone out there who knows:-

a) is this a common fault?

b) is there a cheaper way of trying to solve it?

Incidentally I have already dismantled and had a look at the sensor. It was very dirty but after cleaning the warning lights were still on.

Any advice much appreciated.

Martin (fuseman)