Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P1120: Throttle Position Sensor 1 Circuit: Description
The throttle body with throttle actuator control contains two throttle position sensors with independent 5-volt supplies and grounds. Each throttle position sensor has its own signal circuit which will vary inversely of one another. TP sensor 1 will range from 4.25 volts at idle to 0.59 volt at WOT. TP sensor 2 will range from 0.75 volt at idle to 4.41 volts at WOT. DTC P1120 will set if the ECM detects a continuous or intermittent open or short in the TP sensor 1 signal circuit.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.