The most important function of the TPS is to tell your DME that you are at WOT.
The quick and dirty way to test is to initiate an “E30 Stomp Test”. Turn the key to “On” (not Start) and do 5 presses of the gas. If your CEL illuminates and starts blinking at you, then your DME recognized WOT via the TPS.
If you want to “really” check your TPS, do it at the at the DME, not at the TPS. Not only does this allow you to test the cable, but it’s also a lot more convenient.
Grab some little alligator clip electrical test leads and a paperclip. The pic below shows which pin in the DME cable that you will be testing. If you mark that hole, you’ll never have to look at the pin-out for this again.
Use a multimeter, your test leads, and that paperclip to check that when your throttle goes to the floor, that pin has continuity to ground.
There’s another pin that goes to ground when your throttle is at idle, but I don’t remember which one that is. That’s all the TPS does…signal idle or WOT. In the absence of one of those pins being grounded, the DME assumes your at mid-throttle.