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 P0221: TP Sensor No. 2 Circuit Performance: Description
Throttle Actuator Control (TAC) module contains 2 Throttle Position (TP) sensors with a common 5-volt supply, a common ground and 2 independent signal circuits that vary resistance according to changes in throttle plate position. ECM measures signal voltage from each TP sensor, which is a reduced value of ECM 5-volt reference. As the throttle plate opens from zero percent throttle to wide open throttle, voltage on TP sensor No. 1 signal increases from 0.4-0.6 volt to 4.1-4.4 volts, while voltage on TP sensor No. 2 signal decreases from 4.3-4.6 volts to 0.6-0.8 volt. DTC sets when TP sensor No. 1 and TP sensor No. 2 signals are out of correlation, and TP sensor No. 2 indicates too large a difference in throttle angle based on MAF reading.
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.