How to Clean the EGR Valve for GM Code P1406

by Johnathan Cronk
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GM manufactures a wide range of vehicles from sedans and sports cars to minivans, SUVs and trucks. GM sells these vehicles under many different name brands, such as Chevrolet, GMC, Buick, Cadillac and more. GM vehicles are equipped with internal computers that send signals for the "Check Engine" light to appear when a component has failed. When the light comes on, a code is sent out, which you can read using a scan tool. When code P1406 appears, the Exhaust Gas Recirculation (EGR) valve has failed. Cleaning the EGR valve can sometimes clear the code. It's best to clean the valve before replacing the entire unit.

Step 1

Park the GM and allow the vehicle ample time to cool off, up to a half hour.

Step 2

Open the hood of the vehicle and locate the EGR valve. You can find the EGR on GM models on the intake manifold. Location may vary slightly from model to model, so it's best to refer to your repair manual. The valve looks like a mushroom top component with a hose and electrical connector coming off it.

Step 3

Pull the vacuum hose gently from the valve to remove it. Squeeze the sides of the electrical connector and pull the connector straight off. Place both components to the side to ensure they do not get damaged during the removal process.

Step 4

Use a socket wrench to loosen and remove the two bolts securing the valve to the mount. Turn the wrench counterclockwise until you remove both bolts. You can now remove the loose valve. Lift the valve straight off the mount using some force.

Step 5

Place the EGR valve in a small bowl with about an inch of carburetor cleaner. Make sure only the bottom part of the valve is soaked. Leave the valve overnight to allow the cleaner to penetrate the carbon.

Step 6

Use a wire brush, small pick and a rag to clean the valve. Push open the valve and clean any carbon debris or build up. The valve should now move freely. Allow the valve to air dry completely.

Step 7

Reinstall the valve. Align the valve on the mount so the holes on the valve match the holes on the mount. Insert the two bolts and tighten using the socket wrench. Plug the vacuum hose back into the valve. Reconnect the electrical connector, then push it into place until you hear it click secured. Close the hood of the GM vehicle.

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