General Information

Engine Control
P0123 Throttle Position Sensor 1 Signal Circuit High Input - General Information

Component Location





General Description

The Electronic Throttle Control (ETC) system is made of the components throttle body, Throttle Position Sensor (TPS) 1 & 2 and Accelerator Position Sensor (APS) 1 & 2. TPS 1 & 2 are sharing the same source voltage and ground. The throttle valve opening is control by throttle motor which is controlled by Engine Control Module (ECM). The opposite position indicator shows inverted signal characteristics. TPS 1 output voltage increases smoothly in proportion with the throttle valve opening angle after starting. TPS 2 output voltage decreases in inverse proportion with the throttle valve opening angle after starting. TPS provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.

DTC Description

If the sensor input voltage is higher than the maximum threshold value during 0.14 sec under normal driving condition, ECM sets DTC P0123.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data




Fig.1) Normal waveform of TPS 1 & TPS 2 with no accel pedal depressed under IG ON condition.