Every motor vehicle has an exhaust gas recirculation system in it. When the internal combustion engine has just finished its process of igniting the air and fuel mixture, there are exhaust gases which come out as a result. The function of the EGR system is to prevent those exhaust gases from coming out by redirecting them back into the engine’s cylinders. Once the gases enter the cylinders, they will take the place of some fuel and oxygen. As a result, the toxic emissions get reduced and your vehicle becomes a little more fuel efficient.
Trouble Code P0404
The EGR system depends on a sensor and valve to function properly. They are monitored and controlled by the powertrain control module. If this computerized module detects that the performance of the sensor or valve is not good or unusual, then it will generate trouble code P0404. For instance, the sensor informs the module about the valve’s current position, whether it’s closed, open, or halfway open. These actions are usually in sync with the demands of the engine. But if the powertrain module detects the valve is not opening or closing properly, then it will mean there is trouble.
The movement of the EGR valve must be smooth. If there is any weird jerking or speed in its movements, then trouble code P0404 will generate. You will know when this problem might exist because various symptoms will present themselves. After the “Check Engine” warning light illuminates on the dashboard, you may notice that acceleration causes pre-ignition. You may also notice the engine stalling or running kind of rough. This is a sign that the EGR valve is not in the right position.
If you do not fix this problem, the powertrain control module may deactivate the entire EGR system. Do not expect to pass an emissions test if this occurs. You will also have weaker acceleration and poor fuel efficiency.
Fortunately, getting this problem repaired is not that hard if you go to an experienced mechanic. After they scan your powertrain and see the trouble code P0404 for themselves, they will immediately look at your EGR sensor and valve to see their current health status. In most cases, one or both will need to be replaced. The price of an EGR valve should be anywhere from $150 to $500, depending on the make and model of your vehicle. An EGR sensor will cost much less.