A P0122 code means that the the car's computer has detected that the TPS (throttle position sensor) is reporting too low a voltage. On some vehicles that lower limit is 0.17 - 0.20 volts (V).
DTC P0122
CIRCUIT DESCRIPTION
The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies each TP sensor with a 5-volt reference circuit, a low reference circuit, and a signal circuit.
The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from above 4 volts at idle to below 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from below 1 volt at idle to above 4 volts at WOT.
If the ECM detects TP sensor 1 signal voltage is too low, this DTC sets.
