Q: P0404, P0405, P0171, P0174

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P0404, P0405, P0171, P0174 are all pulling up when I read my codes. I'm just wondering if it's better to replace the only the egr or if it's a sensor?

My car has 181107 miles.
My car has an automatic transmission.

Hello. Thank you for writing in. Due to the p0405 code, you will want to start by replacing the sensor. This is typically easier and cheaper than replacing the EGR unit all together. If the light continues to illuminate, then you will know that the EGR valve will need to be replaced. If you would like to replace the entire unit and sensor in the first place, then you may save yourself the extra time and worry. When doing these repairs, either way, you will want to make sure all of the electrical connections are clean, dry, and tight. Double check the ground connections for the unit as well. There are pros and cons to both repairs that you are considering.

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