2001 explorer sport wont start

Check for an aftermarket remote start and remove it. If no remote start check the battery cable at the starter to see if it's touching the "s" terminal on the starter. I hope this helps. Take care.

check battery and then starter

On the left fender just under the hood

does fuel pump get power? next is it turning over but no start cuz that could be ignition module....or if no crank but good power ...dirty or loose battery cables even at starter.or sometimes starters get hung up in flywheel or stuck on a flat spot if you tap starter while atempting to have someone turn it over this will lots of time free up strarter..

check what the diagnosis machine will give if there is no data then check if the starter crank sensor is getting any power

perhaps the neutral safety switch on the new trans is miss adjusted or bad.while holding foot on brake and holding key to start slowly move the shifter from park to low a out of adj. switch will shoe up by being somewere other than park or neutral like inbetween rev. and park etc

Sounds like the starter drive is shot, best thing to do is replace starter with new or rebuild.

Even though I bought the vehicle new, there was an aftermarket security system installed. The system had a bad diode, so i removed the system and reconnected the factory wires.

clean battery cables and make sure they are good and tight.

disconect the batterie cables and scratch and clean very wheel even if they look ok and make sure any aftermarket alarm is disable and even if batterie looks good try to jump start the van