The exhaust gas recirculation (EGR) valve recirculates a portion of the exhaust gas back into the combustion chamber in order to lower the combustion temperature, which helps your vehicle produce fewer oxides of nitrogen, a major pollutant.
How does the EGR valve work?
The exhaust gas recirculation (EGR) valve is computer controlled and/or electrically or vacuum operated. The valve is commanded open at the appropriate time to also the proper amount of exhaust gas to enter the combustion chamber. This exhaust gas lowers the combustion temperature, reducing the amount of oxides of nitrogen (NOx) created during the combustion process.
Problems with the EGR valve can trigger trouble codes, which will cause the Check Engine Light to come on. The vehicle may also fail emissions tests.
EGR valve problems can cause vehicles to idle roughly.
What are the symptoms related to a bad EGR valve?
In many cases you would be able drive the vehicle with a failed Exhaust gas recirculation (EGR) valve. However, in some cases the engine may run so poorly you cannot drive the vehicle. A non functioning EGR Valve can result in a pinging or rattling noise from engine when it is under load (when accelerating).
More symptoms of a bad EGR valve
Can I drive with a bad EGR valve?
In many cases you would be able drive the vehicle with a failed Exhaust gas recirculation (EGR) valve. However, sometimes the engine may run so poorly you cannot drive the vehicle. If you are hearing a ping or rattling type noise from the engine you should not drive the vehicle.
How often do EGR valves need to be replaced?
Exhaust gas recirculation (EGR) valve replacement is one ot the less common repairs you should expect. Vehicles that are only driven around town on short trips may be more prone to Exhaust gas recirculation (EGR) valve problems as this kind of driving can allow the buildup of carbon deposits in and around the EGR valve. These carbon deposits can restrict the flow of exhaust gases and/or cause the valve to stick open.
How are EGR valve issues diagnosed?
An illuminated check engine light could lead to a fault code indicating a problem with the Exhaust gas recirculation (EGR) valve. In this case, the manufacturer suggested diagnostic procedures should be followed to isolate the cause. Removal of the valve may be required for a visual and functional inspections.
How is a EGR valve replaced?
Once the valve is located and made accessible (on some models this can be very easy and on others it can be quite a challenge), relacement commonly involves unbolting the old valve and installing the new one. Rust can develop on the mounting nuts/bolts so penetrating oil should be used prior to attempting removal. Care should be taken around hot exhaust components. While the valve is off, it is a good time to check the be sure the EGR passages are clear.
The entire EGR system should be inspected and cleaned (if necessary) when an EGR valve is replaced.
