Over Revving Ka

[DROGE2]

Hi I'm a new member so hope this post is ok. I'm looking for help with a problem with my other half's 2003 1.3 Duratec Ka.(49k miles)

Engine management light came on on the way home from work, when we stopped at the local supermarket the engine started revving like mad (continuous high revs, white smoke from exhaust) so I switched the engine off. Would not restart after this so we left it and walked home. I went back later to try again, car started and drove short distance home (bit silly I know but didn't want to call RAC when the car was just around the corner)

Engine MIL remained on, DTC code check registers error P0116, checked the coolant level which was low so topped it up. Left the engine to run to temperature, same symptoms as before ie engine revs normally while engine is cool then continuously at high revs when warm. Only way to stop it is to switch off then it will not re-start until the engine is cool.

There is a dry 'grindy' noise from the water pump area, has this failed,do we just have a duff sensor or worse?

Would like an idea of what's wrong before heading off to the garage so any help would be appreciated.

Cheers