General Information

P0121 Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance

General Information

Component Location





General Description

The Throttle Position Sensor (TPS) is mounted on the throttle body and detects the opening angle of the throttle plate.
The TPS has a variable resistor (potentiometer) whose characteristic is the resistance changing according to the throttle angle. During acceleration, the TPS resistance between the reference 5 V and the signal terminal decreases and output voltage increases; during deceleration, the TPS resistance increases and TPS output voltage decreases.
The ECM supplies a reference 5 V to the TPS and the output voltage increases directly with the opening of the throttle valve. The TPS output voltage will vary from 0.2 - 0.8 V at closed throttle to 4.3 - 4.8 V at wide-open throttle.
The ECM determines operating conditions such as idle (closed throttle), part load, acceleration/deceleration, and wide-open throttle from the TPS. Also The ECM uses Manifold Absolute Pressure Sensor (MAPS) signal along with the TPS signal to adjust fuel injection duration and ignition timing.

DTC Description

Once enable conditions are met, if the number of times that the throttle angle input signal rapidly increases over 30% is greater than or equal to 3 , P0121 is set.

DTC Detecting Condition





Specification





Schematic Diagram





Signal Waveform