Is the p0404 code for a egr valve or egr sensor?

Question

I have a dodge journey sxt with 3.5 liter. I recently changed my air filter and headed for vacation to South Carolina. After fueling in S.C. the vehicle began to hesitate and the engine light came on. I stopped at Advance Auto parts to have it scanned. It pulled up a P0404 code twice. The employee told me it was probably the high percentage of ethenoyl in S.C. and sold be lucas gas treatment and told me to run some tanks of high test. I ran three tanks on the way home in which the light when out and came back on again. My vehicle has about 46,000 miles. Could it be just gas or more likely the egr valve?

Answer 1

P0404 EGR (Exhaust Gas Recirculation) Sensor performance

This code condition is for the EGR , The ECM monitor its position and know when it is open or closed, as a position sensor it becomes its own  EGR sensor. If this was a high concentration of Ethenoyl the 02 sensor will respond as lean bank code condition,