OBD-II Code P0510 — What It Means & How to Fix It

What Does This Error Mean?

P0510 means the closed throttle position switch is not working correctly. This switch tells the engine computer when the throttle is fully closed — meaning your foot is off the gas. When it fails, the engine may idle roughly, hesitate, or surge. The computer relies on this signal to manage fuel, idle speed, and emissions. This should be diagnosed and repaired to restore normal driveability.

Affected Models

All vehicles 1996+
Common in Honda Civic and Accord
Common in Nissan vehicles
Common in older Toyota models
Common in Mitsubishi vehicles

Common Causes

Faulty closed throttle position switch inside the throttle body
Damaged or corroded wiring to the throttle position sensor or switch
Loose or disconnected connector at the throttle body
Carbon buildup on the throttle plate preventing full closure
Misadjusted throttle position sensor or switch

How to Fix It

Locate the throttle body and inspect the throttle position sensor connector. Unplug it and check for corrosion, bent pins, or moisture inside the connector.

The throttle body is on the intake manifold, connected to your air intake tube. It is usually easy to see.
Check the wiring harness from the throttle body back toward the engine computer. Look for chafed wires, melted insulation, or any damage near hot exhaust components.

Wiring near the exhaust can degrade over time from heat exposure.
Clean the throttle body with throttle body cleaner. Heavy carbon buildup can prevent the throttle plate from fully closing, triggering this code.

Spray cleaner on a rag or cotton swab and wipe the inside of the throttle bore. Do not spray directly into a running engine.
Test the throttle position sensor with a multimeter. With the key on and engine off, check that the voltage changes smoothly from closed to open throttle with no dead spots.

A dead spot or sudden jump in voltage confirms a bad sensor.
Replace the throttle position sensor if testing confirms it is faulty. Clear the code and test drive to confirm normal idle and throttle response.

Some vehicles require the TPS to be adjusted to a specific voltage at closed throttle after replacement.

When to Call a Professional

If you are not comfortable working around the throttle body or electrical connectors, take it to a shop. Throttle position sensors typically cost $20 to $100 for the part. Labor is usually $50 to $150. Total repair cost at a shop is typically $100 to $250. Clean the throttle body while you are in there — it only takes a few minutes.

Frequently Asked Questions

Can I drive with P0510?

Yes, in most cases the car will still run. However, you may notice rough idle, hesitation, or poor fuel economy. Driving long-term with this code can affect catalytic converter life. Get it diagnosed soon to avoid additional problems.

What is the closed throttle position switch?

It is a sensor inside or attached to the throttle body. It sends a signal to the engine computer when the throttle plate is fully closed. This tells the computer you have your foot off the gas. The computer uses this to adjust fuel and idle speed.

Will cleaning the throttle body fix P0510?

Sometimes yes. Heavy carbon buildup can prevent the throttle from fully closing. This makes the switch think the throttle is never fully closed. Cleaning often resolves the code if buildup is the cause.