usually when solenoids fail, and due to their being a spring in them,they fail in closed position!!!
k
March 2009
Depends on age of car as to what to what could be causing problem. If an older car most likely stop solenoid knackered. Not necessarily failed due to pump fault, the coils on the solenoid can fail with age. Some solenoids cheap as £30 to replace. Many are easy to remove and test.
Fred
March 2009
stop solenoid is not closing. usual cause is pump internals breaking up and holding plunger open!