GM 25950499 Valve Assembly, Evap Emission Canister Vent Solenoid

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The EGR system meters exhaust gases into the engine induction system through passages cast into the intake manifold. The amount of exhaust gas admitted is regulated by a vacuum or backpressure controlled valve in response to engine operating conditions. Common engine problems associated with the EGR system are rough idling or stalling at idle, rough engine performance during light throttle application, and stalling during deceleration. To check the EGR system, start the engine and manually lift the EGR diaphragm. If the engine stalls or the idle drops considerably, the EGR valve is operating properly. Check all hoses connected to the valve for breaks, leaks, or kinks. Disconnect the vacuum hose from the EGR valve and apply vacuum using a vacuum pump. The engine should stumble or die, indicating the vacuum diaphragm is operating properly. Check the operation of the EGR control solenoid and have the vehicle checked by a qualified repair facility for further testing. If component replacement is necessary, disconnect the vacuum hose at the EGR valve and remove the nuts or bolts securing the valve to the intake manifold or adapter. Lift the EGR valve from the engine, clean the mounting surfaces, and place the new EGR valve with a new gasket. Connect the vacuum signal hose. For the linear EGR valve system, special electronic diagnostic equipment is needed for checking and should be done by a qualified repair facility. If replacement is necessary, disconnect the electrical connector, remove the mounting bolts, and remove the EGR valve. Clean the mounting surface, install a new gasket, and tighten the bolts securely. Connect the electrical connector onto the EGR valve.