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OBD-II · Engine and powertrain (P)

P0221

Throttle/pedal position sensor B range/performance

What it means

Position sensor B does not agree with the expected throttle position or with sensor A.

Symptoms

  • reduced power or limp mode (EPC light on VW group cars)
  • poor or no response to the accelerator
  • raised or unstable idle
  • engine warning light

Likely causes, most likely first

Likely causes, most likely first
No.Cause
01worn sensor track in the throttle body
02dirty or sticking throttle body
03adaptation needed after cleaning or replacement
04connector fault

What to check, step by step

  1. 01Check the battery voltage and charging: low voltage can upset electronic throttle signals
  2. 02Inspect the throttle body connector and wiring for corrosion, oil or broken pins
  3. 03Check the 5 V reference, ground and both position signals with a meter or scope
  4. 04Watch both throttle position signals in live data while the throttle moves: they should change smoothly without dropouts
  5. 05Replace the throttle body (the sensors are usually built in) and run the throttle adaptation