How can an exhaust gas recirculation valve be checked?
How can an exhaust gas recirculation valve be checked? A vacuum-controlled EGR valve is easy to test with a hand-held vacuum pump (see the image). If the EGR valve opens and the vacuum holds for more than a minute, the EGR valve works. If a vacuum diaphragm inside the EGR valve is leaking, the vacuum will drop. Once the vacuum is released, the valve should close fully. How is exhaust gas recirculation used in cars? Since the early 1970s, some form of exhaust gas recirculation (EGR) system has been used to reduce harmful exhaust emissions in vehicles sold in North...