The EGR valve or exhaust gas recirculation valve is a small vacuum powered valve that reintroduces exhaust gas into the engine. An EGR valve is one of the many components of a Ford Focus' emissions system that helps the engine run cleaner. Introducing exhaust gasses into the combustion chamber, helps the engine to maintain a lower operating temperature, which in turn helps to reduce toxic gasses emitted by the engine.
The EGR valve is near the exhaust manifold. Open the bonnet of the Ford Focus and look between the engine and the radiator. The exhaust manifold is bolted to the front of the engine. Look for a valve near the exhaust manifold and connected to the throttle housing by a metal pipe.
Begin by disconnecting the ground cable from the negative battery terminal. Using a wrench, loosen the retaining bolt and pull the clamp off the negative terminal. Disconnect the vacuum hose from the EGR valve by pulling it off. Loosen the clamp nut that secures the EGR valve to the metal pipe. Remove the two bolts that secure the EGR valve to the engine. Remove the valve from the vehicle.
Place the new EGR valve into position using a new gasket between the valve and the engine. Reinstall the two bolts that secure the EGR valve to the engine. Insert the metal pipe into the EGR valve and tighten the clamp nut. Then reattach the vacuum line to the top of the EGR valve by sliding the vacuum hose onto the fitting. Reconnect the ground cable to the negative battery terminal.