what usually happens with stop solenoid is that debris gets stuck under plunger seat and holds it open not allowing it to switch off-- if solenoid fails then it holds in stop position due to spring pressure on plunger.if it has no immobiliser system ,you can take out valve,clean and refit [watch out for spring under plunger] note_if fault persists then your pump may be wearing internally with the worn particles causing your fault!
k, August 2009
