Auto tranny does not shift up or down

96 Geo Metro LSI with 1.3 ltr. 4 cyl engine with auto trans. Trans does not shift automatically up or down. Shifts fine manually moving the shift lever. Speed sensor on side of engine replaced. Still would not shift. Any clues please.
Doug

Any engine codes? If there are no automatic shifts usually the control system is at fault (VSS is one component that could be the reason but apparently not in this case). However there are other components used to generate the shifts - TPS is one you may want to check. Also you should check that the shift switch is working OK. The procedure for checking this is long so if you want to DIY this I would suggest buying the repair manual for the MX17.

Another possibility are faulty shift solenoids. If you only have first in "D" that means both solenoids are energized. If so it sounds like a faulty ECM or a faulty sensor. However, if you only have third in"D", you could have a broken wire somewhere.

Also check the thottle valve cable from the gas pedal to the trans. If it is out of alignment or broken you could get this.