This is a tough one, I would expect a fluctuating idle or high idle when duty cycle is 10% (engine idling @ normal operating temp)

Sbourg has a point.
BUT why then the diagnostics port would give a 10% fixed duty cycle? (potentiometer malfunction)

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified