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P0510 — Closed Throttle Position Switch

Generic OBD-II · all makesPowertrain (engine & transmission)

The P0510 code indicates that the engine control module (ECM) has detected a malfunction in the closed throttle position switch. This means the computer is not receiving the expected signal that the throttle valve is fully closed during idling or deceleration.

Symptoms

What causes it — most likely first

1. Faulty Throttle Position Sensor/Switch

The internal circuitry of the sensor or the specific closed-position switch has failed and no longer sends a signal.

2. Throttle Body Obstruction

Carbon buildup or debris prevents the throttle plate from closing completely, stopping the switch from triggering.

3. Wiring Damage

Frayed, broken, or shorted wires in the sensor harness prevent the signal from reaching the ECM.

4. Corroded Connectors

Moisture or corrosion at the sensor plug creates high resistance or an open circuit.

5. PCM/ECM Failure

An internal fault in the engine control module prevents it from processing the switch signal.

How it's diagnosed

  1. Perform a visual inspection of the throttle body for carbon deposits or physical obstructions.
  2. Inspect the wiring harness and electrical connectors for signs of wear, corrosion, or damage.
  3. Use a multimeter or oscilloscope to verify the switch signal transitions correctly when the throttle is closed.
  4. Clean the throttle plate and housing to ensure the valve can close fully.
  5. Perform a throttle position relearn procedure if supported by the vehicle.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Can a dirty throttle body cause this code?

Yes, if carbon deposits prevent the butterfly valve from seating fully against the bore, the closed-position switch may not be activated.

Should I replace the PCM if I have a P0510 code?

No, it is very rare for the PCM to be the cause. Most cases are resolved by cleaning the throttle body or replacing the sensor and repairing wiring.

Will the car still drive with this code?

Generally yes, but the vehicle may exhibit poor idle quality or enter a reduced-power mode to protect the engine.