87 Aerostar

It may not mean anything. If you didn't turn the wheel at the proper time, the computer may just not have received the proper input from the pressure switch. However, it sounds more like you have a bad power steering pressure switch, or the wiring to it is damaged. I know they exist, and I think they're in the PS pump housing somewhere. I've never actually changed one tho. The purpose of the switch is to tell the computer to increase the idle speed when you're turning the wheel to prevent the extra load from killing the engine.

CJB

They are prone to leakage and easy to change.. look for a tee with a switch in the pressure line. If the switch isnt there, it may have a plug in there. The purpose is to anticipate additional load and increase engine rpm; thus the IAC doesnt have to 'work so hard'.. which COULD result in 'hunting'

I would drain and change it, unless it has tens of thousands miles using type F. In which case, continue it. Who knows what effect changing it might have on seals if you mixed, again.

the pressure swith is on the power stering line it cost about 60 bucks

If you didn't turn the steering wheel during the engine running test, the code

52 will set. If the switch is actually bad, you may not even notice. Look on the high pressure power steering line, It should be screwed into a fitting on the line. 2 wire connector and IIRC, the top of the switch is green.

Thank you, and everyone else for the help. Found the switch and will replace if it causes a problem. The tranny leaks a bit of fluid now and I will probably drive it this way untill the summer, when I will repair it.