P0220 is a generic OBD-II powertrain code indicating a malfunction in the Throttle/Pedal Position Sensor/Switch “B” circuit. The powertrain control module detected an electrical fault or unexpected voltage in this specific redundant sensor circuit.
Because this is a generic code, the definition is universal, but the sensor location varies by vehicle. The code identifies a circuit condition, which does not automatically prove the sensor itself has failed.
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Key Takeaways
- P0220 is a generic OBD-II code indicating a fault in the Throttle/Pedal Position Sensor/Switch “B” circuit.
- The powertrain control module detected a voltage or signal on the secondary sensor circuit that is outside the expected range.
- Possible causes include damaged wiring, poor electrical connections, a failed sensor, or a PCM issue.
- Symptoms often include an illuminated Check Engine Light, reduced engine power (limp mode), and erratic throttle response.
- Diagnosis requires comparing live data from Sensor A and Sensor B and testing the circuit with a multimeter.
P0220 Code Description and Implications
P0220 is a generic powertrain code, meaning its standardized definition applies across all OBD-II compliant vehicles.
The code indicates a Throttle/Pedal Position Sensor/Switch “B” Circuit Malfunction. Modern electronic throttle control systems use dual sensors (A and B) for redundancy and safety.
When the powertrain control module detects that the signal from the “B” circuit is missing, shorted, or inconsistent with the “A” circuit, it stores P0220.
This condition can compromise the system’s ability to verify throttle position, often triggering a fail-safe or “limp” mode to protect the engine.
Common Causes of the P0220 Code
The underlying cause involves an electrical fault in the secondary sensor circuit.
- Damaged, chafed, or broken wiring in the throttle or pedal position sensor harness.
- Poor electrical connections or corrosion at the sensor connector or PCM.
- A failed throttle position sensor (TPS) or accelerator pedal position (APP) sensor.
- A short to ground or short to power in the “B” signal circuit.
- An internal fault within the powertrain control module (rare).
Symptoms Associated With P0220
Symptoms vary based on the vehicle’s fail-safe strategy.
- An illuminated Check Engine Light.
- Reduced engine power or “limp mode” (vehicle limits speed and RPM).
- Erratic idle, stalling, or hesitation during acceleration.
- The electronic throttle control warning light may also illuminate.
MIL behavior varies by application. The Check Engine Light will typically illuminate immediately upon detecting the circuit fault.
Diagnosing the P0220 Trouble Code
Diagnosis must begin by retrieving the code and checking for related throttle or pedal sensor codes using a scan tool.
View live data to compare the voltage or percentage readings of Sensor A and Sensor B. They should typically move in opposite directions or follow a specific correlation map.
Visually inspect the wiring harness and connectors at the throttle body and pedal assembly for damage or corrosion.
Use a multimeter to verify the reference voltage, ground, and signal circuit integrity for the “B” sensor.
Never replace the throttle body or PCM based solely on the presence of the code. Confirm the exact circuit failure before proceeding.
Repairing the P0220 Issue
Repairs must follow confirmed electrical diagnosis.
If testing confirms damaged wiring or a short circuit, repair the harness and seal the connections.
If the sensor fails resistance or signal tests, replace the throttle position sensor or the complete throttle body assembly, as many modern sensors are integrated.
If the accelerator pedal sensor is at fault, replace the pedal assembly.
After replacement, a throttle position relearn or calibration procedure is often required using a scan tool.
Cost Considerations for P0220 Repairs
Exact repair costs depend heavily on the root cause and component accessibility.
Repairing a wire is less expensive than replacing an integrated electronic throttle body assembly.
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Prevention Strategies for Future Occurrences
Electrical faults in the engine bay and footwell are often difficult to predict.
Inspecting exposed wiring near the throttle body and under the dashboard can help identify developing damage from heat, vibration, or chafing.
Keeping electrical connector seals intact may reduce moisture intrusion and corrosion in the sensor circuits.
Troubleshooting Tips and Best Practices
Always consult the exact manufacturer wiring diagram for your vehicle to identify the specific pinout for the “B” circuit.
Do not assume the sensor is faulty without verifying the wiring harness, as chafing against the firewall or engine components is a frequent cause of circuit codes.
On drive-by-wire applications, ensure the battery is fully charged during diagnosis and relearn procedures to prevent false codes.
If your vehicle is subject to an applicable technical service bulletin regarding throttle body wiring overlays, verify its applicability.
More OBD-II Codes
| P0201 | P0202 | P0203 | P0204 |
| P0205 | P0206 | P0215 | P0222 |
| P0223 | P0261 | P0262 | P0264 |
| P0121 | P0122 | P0123 | P2101 |
| P2103 | P2104 | P0505 | P0506 |
| P0507 | P0265 | P0267 | P0268 |
Frequently Asked Questions
Is the P0220 code generic or manufacturer-specific?
Yes. P0220 is a generic OBD-II code, meaning its definition as a Throttle/Pedal Position Sensor “B” circuit malfunction is standardized across all compliant vehicles.
Can I drive my car with a P0220 code?
Driving conditions depend on the vehicle’s fail-safe mode. If the vehicle is in limp mode, acceleration and speed will be severely limited, making highway driving unsafe.
What is the difference between Sensor A and Sensor B?
Manufacturers use two sensors to verify throttle position for safety. Sensor A and Sensor B typically output different voltage signals to allow the computer to cross-check the readings.
Will cleaning the throttle body fix P0220?
Cleaning the throttle body removes carbon deposits but does not repair electrical circuit faults. P0220 is an electrical code, so cleaning is unlikely to resolve it.
Can I clear the P0220 code by disconnecting the battery?
Disconnecting the battery may temporarily erase the code, but it does not repair the underlying electrical fault. The code will return once the monitor runs.
What Should You Do About the P0220 Code?
Confirm the exact wiring diagram for your specific vehicle application, then follow the applicable diagnostic procedure.
Because P0220 is a generic code, the definition is universal, but the physical layout of the sensor circuit varies by manufacturer.
Inspect the relevant system and components, perform targeted electrical tests, and confirm the root cause before replacing any parts.
