I need some advice about how to find where the fault is with this.

4 year old auto.

Sometimes the sensors work normally. Other times there is a squeak from a speaker as reverse is engaged and then no noises at all. Or a squeak, then random squeaks while going back but there is nothing behind, the display on the radio will show the sensor beam at full length as the squeak comes and goes.

When there is a fault of this type is the sensors or the control unit or something else?

Any assistance will be gratefully received.

Could be anything from a Sensor to the Controller itself, only a VCDS scan will be able to confirm. Sounds more like a loose wire connection somewhere or one or more of the Sensors though.

I have same issue, one of the sensors was diagnosed faulty, was throwing 2 codes, cant remember what they were.

I am told a new one is £79 ish! I forgot to get the part number to see if I can find it cheaper on ebay etc.

Also how easy are they to change, i think it was the third sensor.

Here's a well written and comprehensive Thread on the subject: http://www.briskoda....ctavia-updated/, hope it helps