Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance
What does P0221 mean?
The P0221 code means the vehicle's onboard diagnostic system has detected: Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance. This is a moderate severity code.
Common Symptoms
- Reduced engine power or limp mode
- Erratic or unresponsive throttle response
- Check Engine Light illuminated
- Engine may stall or idle roughly
- Hesitation during acceleration
Probable Causes (Ranked by Likelihood)
- Faulty throttle position sensor (TPS) B Very High
- Damaged or corroded TPS wiring or connector High
- Throttle body carbon buildup or mechanical failure Moderate
- Failed accelerator pedal position sensor Moderate
- PCM/ECM malfunction Low
Step-by-Step Diagnostic Procedure
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Use a scan tool to read TPS B voltage -- should show 0.5V at closed throttle and approximately 4.5V at wide-open throttle
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Compare TPS A and TPS B sensor readings -- they should mirror each other inversely with no dead spots
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Inspect TPS wiring harness and connector for damage, corrosion, or loose pins
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Clean the throttle body with approved cleaner and retest sensor readings
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If sensor readings remain out of range, replace the throttle position sensor or throttle body assembly
Frequently Asked Questions
Can I drive with code P0221?
You can drive short distances, but the vehicle may enter limp mode with significantly reduced power. Have it diagnosed promptly to avoid being stranded.
What is the difference between TPS A and TPS B?
Most modern vehicles use two throttle position sensors (A and B) for redundancy. They provide inverse voltage signals so the PCM can verify throttle position accuracy. P0221 specifically refers to the B circuit.
Can a dirty throttle body cause P0221?
Yes. Carbon buildup on the throttle plate can restrict movement and cause the TPS B sensor to read outside its expected range, triggering this code.