Powertrain (P-codes)Sensors

P0122

Throttle/Pedal Position Sensor/Switch A Circuit Low Input

Medium severity Moderate to diagnose

What P0122 Means

The throttle position sensor is sending a signal lower than the engine control module expects at any point in its range of motion.

Common Causes

  • Faulty throttle position sensor
  • Damaged or corroded wiring/connector
  • Dirty or worn throttle body affecting sensor contact

Symptoms You Might Notice

  • Hesitation or jerky acceleration
  • Idle may be unstable
  • Check engine light on
  • Possible reduced-power mode in severe cases

What to Check First

  1. 1

    Inspect the sensor's wiring and connector for damage

  2. 2

    Clean the throttle body, since carbon buildup can affect sensor contact on some designs

  3. 3

    Test the sensor's voltage output through its full range and replace if it drops out or reads incorrectly

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