P0121

DTC P0121
THROTTLE POSITION SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM (TH - R)

Description
- A Throttle Position Sensor is provided with a potentiometer which is interlocked with the Throttle Valve shaft.
- This Throttle Position Sensor sends the Engine Control Module (ECM) a potentiometer output signal corresponding to the opening of the Throttle Valve. When the level of this signal exceeds a predetermined value the ECM interprets it as complete closure of the Throttle Valve and makes a control most suitable for the Engine operation with the Throttle Valve fully closed. For correcting error of this signal the ECM is provided with a learning function.
- Thus, the ECM precisely controls the air-fuel ratio during acceleration and deceleration as well as Engine idling.

DTC Detecting Condition
Two consecutive trips with fault.

Trouble Symptom
- Erroneous idling.
- Engine stalls.
- Poor driving performance.