: Dtc P0503 1520 And Transmission Slip

mr keys
05-29-04, 05:46 PM
I have a 99 seville sts which has transmission slip at random. The car can run for days without doing it. When it Does slip the speedo digital and analog becomes erratic and drops to zero.Shifting into 3rd restores drive and speedometer goes back to display present speed. It does not always store a code! but it has displayed once only a P1520 (transmission selector switch illegal combination of contacts for more than 3. secs) and twice a P0503 (vechicle speed sensor int high). and a mil lamp on the dash.It also seems to drink trannie fluid topped up twice! Had it on the ramps and no leaks! where is it going?
I am in the uk (South Wales) and there are no quality people I can go to within 150 miles.
Any And all help would be appreciated very much..