Q: How Do You Replace an EGR Valve?A: Under certain engine conditions, such as pulling a heavy load or climbing a steep hill, an engine can produce too much NOx emissions. Controlled by the PCM, the EGR valve recirculates some exhaust gasses back to the intake manifold to reduce combustion temperatures under these circumstances. On four-cylinder engines, the EGR valve and cooler are mounted underneath the intake manifold, at the left rear of the engine. On 3.7L engines, the EGR valve is located at the rear of the left cylinder head. On 4.0L engines, the electronic EGR valve and solenoid assembly is attached to the rear of the right cylinder head. Disconnect the electrical connector, remove the EGR tube, and unbolt the EGR valve. For four-cylinder engines, disconnect the cable from the negative terminal of the battery. Drain the cooling system. Remove the engine cover and disconnect the EGR valve electrical connector. Disconnect the hoses from the EGR valve cooler, then remove the bolts and detach the EGR pipe from the housing. Remove the EGR valve housing mounting bolts, then remove the housing, valve, and cooler assembly from the engine block. Remove the bolts and detach the EGR valve from the housing. Remove all traces of gasket material from the valve and housing. Install the valve to the housing, using a new gasket. Tighten the bolts. Position the housing/valve/cooler assembly against the engine block, install the bolts, then tighten them. Connect the EGR pipe to the housing, using a new gasket, and tighten the bolts. Reconnect the electrical connector and install the engine cover. Refill the cooling system. For V6 engines, the installation is the reverse of removal. When replacing the EGR valve, use a new gasket. When replacing the EGR pipe, replace the gasket at the EGR valve end, and a seal at the intake manifold end (3.7L V6 engine) or a new gasket at the flange (4.0L V6 engine).