How to tell the difference between throttle position sensor bad or pedal position sensor bad?

Hello,

Can you tell me exactly what issue you are facing with?
On this vehicle the throttle position sensor is part of the throttle body, and the pedal sensor is located under the dash.
Generally speaking, the throttle position sensor / throttle body will trigger the check engine light.

https://www.2carpros.com/articles/how-a-throttle-body-works

So, if the check engine light is illuminated, the best first step would be to scan and retrieve the code(s). That can help with the diagnostics.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Let me know what you are experiencing.

Thank you.

yes, the throttle position sensor in part of throttle body assembly. The pedal position sensor is under dash part of gas pedal I get no check engine light even when goes into limp mode. ran scanner also showing no code but if I turn ignition 3x's I get code 2122 on dash screen.

One of the most common causes for limp mode is having a dirty throttle actuator.
Dirty actuator will not bel able to provide correct data to the ECM and that can trigger the limp mode.

Take a look at this helpful guide:

https://www.2carpros.com/articles/reduced-power-limp-mode