The exhaust gas recirculation system, also known as the EGR system, is an emission system that is found on many road going cars and trucks. Its purpose is to recirculate exhaust gases that have exited the engine, back into the intake manifold so that they can be reburned. This dilutes the amount of oxygen coming into the engine by replacing some of it with inert gases, which reduces the NOx levels, and temperature of the mixture.
The EGR system is controlled by the EGR control solenoid. When the EGR control solenoid is activated, a passage is opened up that allows exhaust gases into the intake manifold. The EGR solenoid is controlled by the engine computer, and activated at very specific times in order to achieve the best performance, efficiency, and emissions from the engine.
The EGR solenoid is one of the main components of the EGR system, and any problems with it can cause the system to not function, which can be a major problem in states with strict emissions regulations. Usually a problem with the EGR control solenoid will produce a few symptoms that can alert the driver of a potential problem that should be serviced.
1. Engine performance issues
One of the first symptoms of a possible problem with the EGR control solenoid is engine performance issues. If the EGR solenoid has any issues, it can cause the finely tuned air fuel ratio to be thrown off. This may result in a decreased power, acceleration, fuel economy, as well as an increase in emissions.
2. Engine pings or knocks
Another symptom of a potential problem with the EGR control solenoid is engine ping or knock. If the EGR solenoid fails it can disable the EGR system from recirculating exhaust gases. For certain engines this can cause a large increase in cylinder and exhaust gas temperatures. Excessively high cylinder temperatures can cause engine ping and knock, which can lead to serious engine damage if left unattended.
3. Check Engine Light comes on
An illuminated Check Engine Light is another symptom of a bad or failing EGR control solenoid. If the computer detects an issue with the EGR solenoid, circuit, or system, it will set off the Check Engine Light to notify the driver of the issue. A bad EGR solenoid can cause a variety of different trouble codes, so having the computer scanned for trouble codes is highly recommended.
The EGR control solenoid is one of the most important components of the EGR system. Without it the EGR system will not be able to recirculate the exhaust gases properly, which can lead to issues with engine performance and even emissions. For this reason, if you suspect that your EGR control solenoid may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the solenoid should be replaced.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing EGR Control Solenoid and was authored by Ed Ruelas.