Throttle/Pedal Position Sensor B Circuit Malfunction
What does P0220 mean?
The P0220 code means the vehicle's onboard diagnostic system has detected: Throttle/Pedal Position Sensor B Circuit Malfunction. This is a critical severity code.
Common Symptoms
- Check Engine Light on
- Engine enters limp mode with severely limited power
- Reduced throttle response or no acceleration
- Engine may idle but will not rev above 2,000 RPM
- Erratic or surging idle speed
Probable Causes (Ranked by Likelihood)
- Failed throttle position sensor B (secondary TPS) Very High
- Faulty accelerator pedal position sensor High
- Wiring issue -- open, short, or damaged connector in TPS B circuit Moderate
- Carbon buildup on throttle body affecting sensor operation Moderate
- Failed electronic throttle body assembly Low
Step-by-Step Diagnostic Procedure
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Use a scan tool to read TPS B voltage at closed throttle (approximately 0.5V) and wide open throttle (approximately 4.5V). Compare TPS A and TPS B readings -- they should track together or be inverse of each other depending on design.
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Slowly depress the accelerator pedal while monitoring both TPS A and TPS B. Any dropouts, dead spots, or inconsistencies between the two sensors indicate a fault.
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Disconnect the throttle body connector and check for 5V reference voltage and proper ground.
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Inspect the accelerator pedal position sensor (APP) if the vehicle uses drive-by-wire. It also has dual sensors for redundancy.
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Clean the throttle body with throttle body cleaner to remove carbon deposits that may interfere with sensor operation.
Frequently Asked Questions
Can I drive with code P0220?
No. The engine will likely be in limp mode with severely limited power, making the vehicle unsafe to drive in traffic. Have it diagnosed and repaired before driving.
What is TPS sensor B?
Modern drive-by-wire throttle systems use two throttle position sensors (A and B) for redundancy and safety. If one sensor disagrees with the other, the PCM enters limp mode to prevent uncontrolled acceleration. TPS B is the secondary sensor.
Can I clean the throttle body to fix P0220?
Sometimes. Carbon buildup on the throttle plate can prevent it from seating properly, causing the TPS to read incorrectly at closed position. Cleaning the throttle body resolves this in some cases. However, if the sensor itself has failed internally, the throttle body must be replaced.