I just got a Bafx code scanner and I'm running it with the Torque lite app. The first thing I did was monitor the throttle position. Key on, engine off throttle closed reads 13%, wide open throttle reads 73%. Shouldn't it be 0 and 100? (I did try the same thing on a different vehicle and got 0 and 100%). The voltage at the tps is .54 closed throttle and 3.56 wide open. I'm wondering about the 3.56, isn't that a bit low? Throttle opens/closes freely, no binding. No codes and the truck runs fine but I'd like to know where that other 27% of the throttle went.

 

I would expect the voltage to be 4.8ish wot.
as far as the percent openings...even at engine off, the throttle is open slightly. I was informed at a training course...80% the pcm is seeing this as wot.

 

It cant be 0%. That would be completely closed and the engine would not run....

 

The engine will still run with the throttle completely closed because of the IAC. The other vehicle I tried the tps monitor on did show 0-100%.

Will the voltage get lower as the tps gets older/worn out?

 

The PCM learns 'zero' values for the tps at startup, after the battery has been disconnected. Different companies use different values for 'closed' and 'wot'...... so, basically, the PCM expects to see voltage under 1 volt, at closed throttle, and greater than 3.5 at wot. Programming takes care of the rest.