i need a new yaw sensor im told its attached to the rack , has anybody fitted one if so what sort of job is it thanks. ken p

The PAS sensor is well covered.

Fabia-vrs.com - Replacing the Fabia PAS sensor

But despite what some people think the PAS sensor is NOT a Yaw sensor. a YAW sensor (if fitted) monitors the Yaw angle. Yaw motion is a side to side movement of the nose of the car and is a requirement for ESP systems. If you dont have ESP then you dont have a Yaw sensor.

The steering angle sensor just detects that the steering wheel is being turned by a hall effect signal so the pump can provide assistance.

Common missconception is that if your PAS light has come on it will be the sensor, although this is quite common on earlier models on or about 2002MY the sensors were changed for a different set up and very rarely fail. Much like the engine management light its one light for many faults. They really need to be diagnosed with workshop equipment.

Most common cause of failure of the PAS system is a battery or charging fault. As at max load the PAS pump can draw upwards of 60 amps from the battery. This causes the lights to flicker (as they do to some degree anyhow, they always will). If the battery isnt in A1 condition it wont be able to power the steering system.

whats happening to mine is the lights flicker not just the headlights but all of them even when the car is stationary. if you open the door with the engine running with no other lights on the interior light flickers. now and agian some of the power steering assistance is lost but there is no dash warning lamps on its a 2001 1400 16v thanks

I'd get your alternator and battery checked then.