Throttle Position Switch

The throttle position switch is mounted on the front side of the throttle body, where it signals idle and full throttle conditions to the ECU. The ECU, when it receives a full throttle or idle signal fron the TPS, adjusts the fuel/air mixture for these operating conditions.
When the throttle is in the idle position, the TPS signals the ECU that idle enrichment is needed. The TPS also cancels the input to the oxygen sensor during coast-down to keep the system from being affected by excessive oxygen at that time.

Click on image for internal view of TPS.