The exhaust gas recirculation, or “EGR", system on your vehicle serves to reduce engine emissions by introducing or “recirculating” a small amount of exhaust gas from the exhaust system back to the engine intake. This helps to burn away any fuel that was not completely burnt during the combustion process. It also reduces the level of oxygen that enters the engine cylinders, thereby reducing combustion temperatures and reducing harmful nitrogen oxide. The result is a more efficient engine with fewer hydrocarbon emissions.
The EGR vacuum solenoid is an electronically controlled vacuum valve that distributes engine vacuum to the EGR valve when called upon by the vehicle’s computer, the engine control module (or ECM).
In some cases, you might not immediately notice signs of a bad EGR vacuum solenoid. Symptoms can vary depending on whether the solenoid fails to open properly or close properly. If your EGR vacuum solenoid fails, you might notice the following signs:
The EGR vacuum solenoid can be located either on the engine, near the engine, or on the firewall behind the engine. Therefore, a technician will likely remove the upper engine cover for access. Other wires, hoses, or components might need to be moved as well. It is common to disconnect the negative cable on the battery, taking care to preserve the vehicle computer memory. From there, the technician will disconnect the vacuum lines connected to the solenoid and unplug the electrical wire connector. The solenoid is removed from the vehicle by unfastening the retaining screw, bolt, or clip.
Once the new EGR vacuum solenoid has been secured in place, the electrical plug and vacuum lines are reconnected. All other components that were moved or removed for access are put back into place and the solenoid is tested for proper operation. The technician might need to clear the diagnostic code from the ECM using a scan tool. Your vehicle will likely be road tested as well.
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