Water temp past 90 and revs holding at 1000

[NathanGlover]

Just started my audi up and was all fine went for a drive to let it warm up but the water temp went past the usual 90 where It stays and revs was holding a 1000.

ANy ideas why this would be?

 

[Dani_B19]

Thermostats knackered

 

[NathanGlover]

I've just turned it off and back on and it's fine again.

 

[Dani_B19]

Scan for fault codes, might be a dodgy cts sensor.