The Electronic Throttle Control(ETC) system which is composed of throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2 controls the mass of airflow by driver's intention. The throttle valve opening is control by throttle motor which is controlled by ECM. TPS is a variable resistance and its value is cahnged by open angle of throttle valve.
ECM sends DTC P0121 if the difference between the throttle valve position value calculated by TPS1and the designated value by ECM is over certain value when the TPS2 is abnormal.
Item
Detecting Condition
Possible Cause
DTC Strategy
Plausibility check between
Poor connection
TPS
ECM
Enable Conditions
IG "ON"
Threshold Value
| TPS1 position - TPS2 position | > 6.3%
Diagnostic Time
0.14sec
MIL ON Condition
5 sec
Normal waveform of TPS1 & TPS2 with no accel padal depressed under IG ON condition