I have attempted to have changed out my map sensor, the power steering pressure switch and having the transmission fluid & filter changed today (it needs it)... The problem won't resolve itself. After reading several comments on this site today, I see that this is not necessarily an uncommon occurrence. I would like to know what is causing this problem. When I take the car to the mechanic, they run the diagnostic and advised that I needed to correct the 'pressure control switch,' this should fix the problem... Further advised, we'd need to work backwards to correct the problems within the system to determine exactly the problem. Can you help?