what this code means p0121
Throttle position sensor or circuit, first thing is check the connector, make sure it is clean and the pins are secure, if that looks good then a live data scanner can see if there is a problem with the sensor itself.
po121 has to do with the TPS as tennisshoes says above. Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the Wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.
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