How much does it cost to fix P0510?

DIY repair typically costs $15–$100 for parts. Professional repair runs $120–$400 including parts and labor.

P0510

Powertrain

Moderate

Closed Throttle Position Switch Malfunction

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The P0510 code indicates a malfunction in the closed throttle position switch. This switch (often built into the throttle position sensor) tells the PCM when the throttle plate is fully closed — an important signal for controlling idle speed, fuel cut-off during deceleration, and transmission downshift timing.

When the PCM can't determine whether the throttle is closed, it loses the ability to properly manage idle speed and deceleration fuel control. You may notice an unstable or rough idle, stalling when you take your foot off the gas, or the engine holding higher RPM than normal at idle. The transmission may also behave oddly during deceleration because it uses the closed-throttle signal to determine when to downshift.

Diagnosis begins with checking the throttle position sensor output with a scan tool — at idle with the throttle fully closed, the TPS should read between 0.4V and 0.9V on most vehicles. If it reads higher, the throttle plate may not be closing fully due to carbon buildup (try cleaning the throttle body first) or the TPS needs adjustment or replacement. On older cable-throttle vehicles, the TPS is adjustable and may just need to be repositioned. On newer drive-by-wire vehicles, the entire throttle body may need replacement if the integrated sensor has failed.

Severity

Moderate — Address SoonThis Week

Symptoms

•Rough or unstable idle speed
•Engine may stall when returning to idle from higher RPM
•Higher than normal idle speed
•Hesitation or stumble during deceleration
•Transmission may not downshift properly during deceleration

Likely Causes

Faulty throttle position sensor or closed-throttle switch40%

The internal switch or sensor element that detects when the throttle is fully closed has failed, sending incorrect status to the PCM.

Throttle position sensor out of adjustment25%

The TPS mounting has shifted or the throttle cable has stretched, so the sensor doesn't register the closed position at the correct throttle plate angle.

Wiring or connector issue in TPS circuit20%

Damaged wires or a loose connector in the throttle position sensor circuit cause the closed-throttle signal to be lost or intermittent.

Carbon buildup preventing full throttle closure10%

Deposits on the throttle plate or bore prevent it from returning to the fully closed position, so the closed-throttle switch never activates.

Throttle body or motor failure (electronic throttle)5%

On drive-by-wire vehicles, the electronic throttle body motor may not return the throttle plate to the fully closed position.