How to clean a throttle body: A Step-by-Step Guide (2024)

Learn how to clean a throttle body cleaning using this step-by-step method

Over time, carbon deposits and dirt can accumulate on the throttle body, causing a variety of issues such as rough idling, poor acceleration, hunting idle, and decreased fuel efficiency. Cleaning the throttle body can restore optimal performance and fuel economy. This guide will walk you through the way to clean a throttle body safely and effectively.

Here are the tools and supplies you need to clean your throttle body

• A can of aerosol throttle body cleaner— I recommend the CRC brand cleaner
WARNING: Do NOT use carburetor cleaner. The solvents in carb cleaner can damage some of the plastic parts used in an electronic throttle body.

• Clean rags and an old toothbrush— Used to wipe off carbon deposits and brush off stubborn buildup
• A new throttle body gasket— They’re cheap and it doesn’t pay to try and reuse the old gasket even if it looks ok.
• Hose clamp pliers and hose pinch tools— Some throttle body units have engine coolant lines attached. Those may have to be disconnected and pinched off to avoid losing coolant if you remove them from the throttle body.
• Socket set and ratchet— It’s best to remove the throttle body from the intake manifold to gain access to all the carbon buildup. Depending on the fasteners used, you may need a set of hex, Torx, or security bits

How to perform a throttle body cleaning

Safety first

Never clean an electronic throttle body while it’s on the engine. You must remove it and clean it off the vehicle. Here’s why:

• An electronic throttle body is built with a powerful motor and a gear reduction set that’s strong enough to cut off your fingers! If you force the throttle plate open while the unit is on the vehicle, it will try to close and may cause injury.

• In addition, you need access to the backside of the throttle plate, something that’s impossible to clean while it’s still on the vehicle.

• Finally, you should never spray liquid cleaner directly onto the throttle plate because it can wick into the electronics and gearbox and damage the components.

Electronic throttle body cleaning procedure— Step 1: Disconnect and label the air duct and hoses

• Disconnect the negative battery terminal to prevent accidental activation of the radiator fan.

• Disconnect the air duct from the throttle body. Most air ducts are attached with worm drive clamps or plastic snap clamps. Undo the clamps first. Then check for any sensors in the air duct. If you find sensors, disconnect the electrical connectors and label them. If you can’t remove the clamps, leave this job to the professionals.

• Find and label the vacuum hoses going to the throttle body. They must re-attach to the same ports or you’ll have problems later. TIP: Use removable (blue) masking tape and number both the hose and the port using a Sharpie marker.

• Disconnect and pinch off any coolant hoses connected to the throttle body. Note where they go so you can reconnect to the same ports when you’re done.

• Remove the electronic throttle body from the intake manifold and place it on shop rags on your workbench.

Electronic throttle body cleaning — Step 2: Clean carbon buildup with throttle body spray cleaner and a rag

Wear rubber gloves for the following steps.

• Spray the cleaner onto a rag and wipe the liquid onto the throttle plate and throat. Let it soak.

WARNING: Do not spray throttle body cleaner directly onto the throttle plate. The cleaner can wick into the electronic portion of the throttle body and damage the circuit board and motor

• Wipe off the softened carbon buildup with a rag. For stubborn deposits, use an old toothbrush. Do not use any metal tools to scrape the carbon. That can damage the non-stick coating inside many throttle bodies.

Wipe carbon buildup from the bore and the front and backsides of the throttle plate. Make sure you remove carbon deposits from the top and bottom edges of the throttle plate.

Install the cleaned throttle body— Step 3

• Install the new throttle body gasket.
• Reconnect all hoses that you removed from the throttle body
• Insert all bolts and torque to spec.
• Perform the electronic throttle body relearn for your engine.

Perform a throttle body relearn procedure— Step 4

The ECM is self-learning and adjusts the baseline home position as the throttle body accumulates carbon buildup. The ECM can’t know that you’ve cleaned off that carbon buildup unless you perform a throttle body relearn procedure. The relearn procedure for cleaning is the same procedure you’d use if you disconnect the battery cables. Find the procedure in your owner’s manual or online. Here are some links to the GM and Ford procedures.

How to clean a mechanical throttle body

Mechanical throttle bodies don’t require removal for cleaning.
• Open the throttle plate manually and hold it open while you spray the throttle body cleaner on the carbon buildup. Then spray the cleaner directly onto the throttle plate and shaft. Let it soak
• Wipe off the carbon buildup with a rag

Spray the rag and continue wetting and wiping the carbon buildup until it softens.

What causes carbon buildup in the throttle body?

Crankcase gasses cause throttle body carbon buildup

When you shut down the engine, crankcase vapors rise to the top of the engine. From the valve cover, the vapors make their way into the intake manifold and the throttle body. The vapors contain exhaust, soot, water vapor, and some unburned fuel. As the engine cools, those vapors condense on the intake side of the throttle body, especially near the throttle plate. The carbon buildup hardens as it cools. As the buildup increases, it reduces airflow through the throttle body.
©, 2015 Rick Muscoplat