P0220: Throttle/Pedal Position Sensor/Switch "B" Circuit Malfunction
Check Engine light illuminated; possible reduced throttle response, engine hesitation, or limp mode limiting power
Overview
P0220 throttle pedal position sensor B circuit malfunction indicating throttle/Pedal position sensor or wiring fault causing out-of‑range voltage to PCM
Common Symptoms
- Check Engine Light illuminated
- Poor or erratic throttle response
- Engine hesitation or stumbling during acceleration
- Reduced engine power or limp mode activation
- Hard starting or stalling in some cases
Most Common Causes
Sensor may send erroneous voltage outside expected range, triggering the code
Some vehicles integrate pedal position sensing correlated with TPS data
Corroded or loose connectors and wiring can cause intermittent or incorrect signals
Contaminated throttle body can affect sensor operation indirectly
Rare but possible if all sensors and wiring test good
Diagnostic Steps
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Use an OBD‑II scanner to confirm P0220 and check for related codesExpected: P0220 present; possible additional codes like P0120/P0221Interpretation: Confirms throttle/Pedal position circuit fault signals
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Visually inspect wiring and connectors at throttle body and pedal assembliesExpected: Check for corrosion, loose clips, broken wiresInterpretation: Poor connections or damaged wiring can cause erratic signals
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Measure TPS/APP sensor voltage with multimeter while slowly varying throttleExpected: Smooth voltage change within manufacturer specification (e.g., ~0.5 to ~4.5V)Interpretation: Erratic or flat voltage trace indicates sensor or circuit fault
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Perform continuity checks on signal and ground circuitsExpected: Continuity between sensor ground and PCM ground; signal wire continuityInterpretation: Broken or shorted wires identified if continuity fails
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Replace suspect sensor or repair wiring and clear codes; test driveExpected: Code clears; symptoms resolvedInterpretation: Successful repair if code does not return
Repair Solutions
Costs vary with extent of harness repair
Includes part and labor; varies by vehicle
Required on some models with integrated pedal sensors
Helpful if contamination affects sensor performance
Rare; pursue only after ruling out sensors and wiring
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Replacing TPS without checking wiring and connectors
- Mistaking APP sensor or floor mat interference as sensor failure
- Assuming only throttle body contamination is cause without testing electrical signals
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