did you find out what the problem was ,and get it sorted, im having same problem, ive changed pump,as old one died,but it seems its like pump is running all time and humming loudly ,but it seems to be running all the time

mines the same had to turn radio up car runs fine yesterday when climbing up a steep hill the engine lost speed and power and the engine management light would flash on as soon as levelled out or went down hill the car run fine again and engine management light went out again today...