A dirty or worn throttle position sensor B track inside the throttle body assembly.; Corroded, loose, or damaged wiring and connector pins in the sensor B circuit.; A failing electronic throttle body actuator or internal sensor assembly.; A binding or carbon-fouled throttle plate that prevents the sensor from sweeping smoothly.; An intermittent open or short in the sensor B signal or ground circuit.; A faulty accelerator pedal position sensor that the computer cross-checks against the throttle sensors.; A software or calibration issue in the engine control module, though this is less common.

DTC codes / P02xx · Fuel and air metering (injector circuits) / P0221

P0221Throttle Position Sensor B Circuit Range/Performance

Q: What does code P0221 mean?

Throttle Position Sensor B Circuit Range/Performance. P0221 means the engine computer has detected that the signal from throttle position sensor B is outside the expected range or is not performing as it should compared with the other throttle sensor. The computer compares the two throttle position sensor signals, and when sensor B's voltage does not rise or fall in a plausible way, it stores this code and typically commands reduced engine power.

P0221 means the engine computer has detected that the signal from throttle position sensor B is outside the expected range or is not performing as it should compared with the other throttle sensor. The computer compares the two throttle position sensor signals, and when sensor B's voltage does not rise or fall in a plausible way, it stores this code and typically commands reduced engine power.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

The check engine light or electronic throttle control warning light is illuminated on the dashboard.
The engine may enter limp mode with severely reduced power and a maximum speed limit.
The accelerator pedal may feel unresponsive or the engine may hesitate when you press it.
The engine may idle at an abnormally high or erratic speed.
The transmission may shift harshly or refuse to shift normally because it relies on throttle position data.
Often no symptoms besides the warning light, especially if the fault is intermittent.

Common causes, most likely first

A dirty or worn throttle position sensor B track inside the throttle body assembly.
Corroded, loose, or damaged wiring and connector pins in the sensor B circuit.
A failing electronic throttle body actuator or internal sensor assembly.
A binding or carbon-fouled throttle plate that prevents the sensor from sweeping smoothly.
An intermittent open or short in the sensor B signal or ground circuit.
A faulty accelerator pedal position sensor that the computer cross-checks against the throttle sensors.
A software or calibration issue in the engine control module, though this is less common.

How to diagnose and fix it

Scan all modules and record freeze-frame data for P0221 before clearing anything.
Inspect the throttle body connector and wiring for corrosion, chafing, or loose pins.
Back-probe sensor B signal and ground wires and watch the voltage sweep smoothly as the throttle is moved.
Clean the throttle body bore and plate with throttle-safe cleaner and recheck the sensor sweep.
Compare sensor A and sensor B voltages on a scan tool to confirm which sensor is out of range.
Replace the electronic throttle body if the internal sensor track is worn or the actuator is faulty.
Clear the code, perform a throttle relearn, and road test to confirm the repair.

Why throttle body cleaning often fixes P0221

Carbon buildup on the throttle plate can make the sensor B voltage jump or drop out at certain throttle angles, which sets P0221 even though the sensor itself is fine.
A worn spot in the sensor B track often shows up only when the throttle is held at a steady angle, so a quick snap test on the scan tool can miss it.
Technicians sometimes replace the throttle body when the real problem is a corroded ground wire shared with other sensors, so always check ground integrity first.
P0221 can be set by a binding throttle plate after a battery disconnect or a dirty bore, so a relearn and cleaning may be all that is needed.
The accelerator pedal sensor is cross-checked against the throttle sensors, so a faulty pedal sensor can trigger P0221 without any throttle body fault.

Can I keep driving with P0221?

You can usually drive to a shop if the vehicle is not in limp mode, but avoid heavy acceleration and highway merging because the computer may suddenly reduce power. If the engine enters limp mode or the throttle feels unresponsive, stop driving and have the vehicle towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.