P0221 - OBD-II Trouble Code

Auto Systems and Repair

Throttle/Pedal Position Sensor/Switch "B" Circuit Range/Performance Problem

Our emissions expert has put together the following information about the P0221 fault code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the code.

OBD II Fault Code

  • OBD II P0221

Fault Code Definition
The Throttle Position Sensor/Switch is located on the Throttle Body of the Intake Manifold and the Pedal Position Sensor/Switch is located on the Accelerator Pedal. These sensors provide precise input from the driver's foot in terms of how much power is needed—and how urgently—from the engine.

As the Throttle Position Sensor is rotated from its base resting position to full acceleration, it sends a decreasing voltage signal to the Powertrain Control Module (PCM). This decreasing or increasing voltage signal is used by the PCM to manage the Air Fuel Ratio and Spark Timing of the engine as well as other emissions system components.

Symptoms

  • Check Engine Light will illuminate
  • In many cases, no abnormal symptoms may be noticed
  • In some cases, the engine may be hard starting
  • In some cases, the engine may hesitate during acceleration

Common Problems That Trigger the P0221 Code

  • Defective Throttle/Pedal Position Sensor or Switch
  • Dirty or carbon-filled Throttle Bore
  • Torn or jammed floor mats
  • Faulty or corroded Throttle/Pedal Position Sensor/Switch wiring or connections

Common Misdiagnoses

  • Throttle Position Sensor is replaced when the real problem is a dirty or carbon-filled Throttle Body
  • Throttle/Pedal Position Sensor is replaced when the real problem is a poor connection or chafed wiring
  • Pedal Position Sensor is replaced when the real problem is torn or damaged floor mats
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