P0120 Throttle/Pedal Position Sensor/Switch "A" Circuit

Powertrain Severity: High Generic OBD-II

Electrical fault in the throttle position sensor A circuit.

Common causes

  • Faulty throttle body sensor
  • Wiring or connector damage
  • Water in connector

Symptoms

  • Check engine light
  • Limp mode with limited throttle
  • Erratic idle

What to check

  1. Inspect the throttle body connector
  2. Check reference voltage and ground
  3. Review both TPS signals with a scan tool

Manufacturers may add their own detail to generic codes. If your vehicle shows a different description for P0120, follow the service information for that make and model.

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