Troubleshooting
DTC P0121 Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance ProblemCIRCUIT DESCRIPTION
DTC Detecting Condition:
Detection Item:
The throttle position sensor is mounted in the throttle body and detects the throttle valve opening angle. When the throttle valve is fully closed, a voltage of approximately 0.3 - 0.8 V is applied to terminal VTA of the ECM. The voltage applied to the terminals VTA of the ECM increases in proportion to the opening angle of the throttle valve and becomes approximately 3.2 - 4.9 V when the throttle valve is fully opened. The ECM judges the vehicle driving conditions from this signal input from terminal VTA, and uses it as one of the conditions for deciding the air- fuel ratio correction, power increase correction and fuel-cut control etc.
HINT: After confirming DTC P0120, use the OBD II scan tool or hand-held tester to confirm the throttle valve opening percentage.
INSPECTION PROCEDURE
HINT: Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.
Replace throttle position sensor