P0221 Fault Code

P0221 OBD-II Trouble Code Short Description

Throttle Position Sensor/Switch B Circuit Range/Performance

What does trouble code P0221 mean?

The P0221 fault code refers to a problem with the throttle/pedal position sensor/switch B circuit range/performance. In simpler terms, it means that the engine control module (ECM) has detected a discrepancy between the expected position of the throttle pedal and the actual position.

There are several potential causes for this fault code, including a faulty throttle position sensor (TPS), a damaged or corroded wiring harness, a problem with the accelerator pedal assembly, or an issue with the ECM itself. Symptoms of a P0221 code may include reduced engine performance, rough idling, or difficulty accelerating.

To solve this problem, a mechanic will first diagnose the root cause of the issue by running diagnostic tests or inspecting the relevant components. In some cases, it may be as simple as replacing a faulty sensor or clearing a loose connection. However, if the problem is related to the ECM or accelerator pedal assembly, it may be a more complicated and expensive repair.

When this code appears, it is important to take immediate action to identify and repair the underlying issue, as neglecting to do so can lead to further engine damage or safety hazards.


What causes the P0221 code?

P0221 is a fault code that indicates a problem with the throttle/pedal position sensor/switch B circuit range or performance. Here are some possible causes of this fault code:

  • Faulty throttle/pedal position sensor/switch
  • Damaged wiring or loose connections in the throttle/pedal position sensor/switch circuit
  • Corrosion or oxidation in the throttle/pedal position sensor/switch circuit
  • Malfunctioning throttle body or fuel system
  • Faulty electronic control module (ECM) or powertrain control module (PCM)

If you experience this fault code in your car, it is recommended to take it to a certified mechanic or dealership for diagnosis and repair.

Possible Solutions

How to fix P0221?

If you're seeing a P0221 fault code on your car, this indicates that there is a problem with the throttle position sensor circuit. This sensor is responsible for sending signals to the engine control module (ECM) about the position of the throttle, which in turn affects the engine's performance.

Here's how you can fix the issue:

  1. Check the wiring harness: The first thing you want to check is the wiring harness that connects the throttle position sensor to the ECM. Look for any signs of corrosion, damage or wear and tear, as this could be causing a bad connection.

  2. Test the sensor with a multimeter: Use a multimeter to test the resistance of the throttle position sensor. The sensor should have a specific range of resistance, so if it falls outside of that range, you'll need to replace it.

  3. Replace the throttle position sensor: If the sensor is faulty, the best course of action is to replace it altogether. You can do this yourself if you feel comfortable working on your car, or you can take it to a mechanic.

  4. Reset the ECM: Once you've replaced the sensor, you'll want to reset the ECM by disconnecting the battery for a few minutes. This will clear any stored fault codes and allow the ECM to recalibrate itself.

By following these steps, you should be able to fix the P0221 fault code on your car. If the issue persists, it's always best to take it to a mechanic to diagnose and fix the problem.


  • What is the definition of P0221?

    P0221 is a diagnostic trouble code (DTC) in the On-Board Diagnostic (OBD) system of vehicles. It indicates that there is a problem with the throttle/pedal position sensor/switch B circuit, which is typically caused by a faulty sensor, wiring issues, or an engine control module (ECM) problem.

  • What are the symptoms of P0221?

    The most common symptoms of P0221 include an illuminated Check Engine light, reduced engine power, hesitation or stumbling during acceleration, and poor fuel efficiency. In some cases, the engine may not start or may even stall while driving.

  • How is P0221 diagnosed?

    Diagnosing P0221 typically involves using a scan tool to retrieve the DTC and then performing a visual inspection of the throttle/pedal position sensor/switch B circuit wiring and connectors. A technician may also use a multimeter or oscilloscope to test the sensor and associated circuits. Additionally, the ECM may need to be reflashed or replaced if it is found to be the cause of the problem.

  • How is P0221 treated?

    Treating P0221 involves identifying and fixing the underlying cause of the problem. This typically involves repairing or replacing the throttle/pedal position sensor/switch B circuit wiring or connectors, replacing the sensor, or replacing the ECM. In some cases, a simple reset of the ECM may be all that is needed to clear the code and restore normal function.

  • Can I still drive my vehicle with P0221?

    While it is possible to continue driving with a P0221 DTC, it is not recommended because the reduced engine power and potential for stalling can cause unsafe driving conditions. Additionally, driving with a malfunctioning throttle/pedal position sensor/switch B circuit can cause further damage to the engine or other related components over time, resulting in more costly repairs down the line.