Yup, Steve is probably right, if it were solenoid, you would most likely get a solenoid code. Valve body wear at the main pressure regulator valve area generally causes it, or, the converter itself worn. Make sure also that the one you get is GUARANTEED rebuilt, some cheaper places merely clean inside as best they can, throw spraypaint on it and call it "new". Look for a cut line and new weld around the outside diameter, means scraping some paint off it. When I pulled my Zetec, I intended to pull CD4E trans ONLY, would not work going up, even with pulleys and damper pulled off, still not enough room to clear flywheel/converter studs. Built using 4X4s an imitation of Ford 3 point engine support that sits inside edges of fenders. No need to remove hood. Used 1/2 all thread 36" long and short pieces of chain to make 3 screw type hoists so could level it front/rear at reinstall. Entire tool cost about $40. Dropped entire motor/trans maybe 6" at a tilt then broke them apart, dropped trans out by itself. Of course subframe was removed, also exhaust sys for fear of damage to flex joint. Most all other engine wiring, hoses left on. Car sat for 4 months with passenger side engine mount on and bricks/boards under oilpan to support engine while no trans. Put subframe back on so could reinstall wheels to please the city. I found some specific deep sockets that fit the alignment holes in subframe/main body perfect (tight) and with no alignment at all car drove perfectly after job done. My trans blew the forward/direct clutch cylinder, that's VERY common on these trannys also, if you go in, you need to change that part while there. Strongly suggest a NEW cylinder, used may look good and break in 5 minutes.