Code PO500
 

First of all can someone please tell me how many vehicle speed sensors are there and where they are located on my 1996 es300. My car is shifting long and hard sometimes when check engine light is on but runs just fine when light goes off. At first it would come on for a day or so and then not again for months now its been on for a week and problems seem worse and more frequent. I've located the three wire speed sensor seated on the trans but at the parts store they printed a photo of two different looking sensors one 3 wire metal with longer shaft and the other 2 wire plastic with very short shaft and a hole

There is one, on top of the transmission. You sure the connector is 3 wire? The ones I've seen are two wire that look like this, but the parts diagram does show a 2nd part number so maybe there are two types although I have only seen the one.

The 3 wire part I found on top of the trans looks like http://thumbs2.ebaystatic.com/d/l225...IkhI6_3GQg.jpg

Is this an either/or thing or are there two different locations

Just look at the connector on your car to verify what you have. If still in doubt give your VIN to a Lexus parts person and they will tell you.