Q: P0404, P0405, P0171, P0174

asked by on

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.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. P0404, P0405, P0171, P0174

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Check Engine Light with P0174 code

As you know, this code relates to a lean fuel condition which can be caused by many different things, some of which you have already addressed. The oxygen sensors, which are part of your emissions system, read exhaust gases to...

Q: Main relay, EMS1 fuses, and EMS2 fuses are missing. Do I need these parts?

Hi there. The codes are coming up for the camshaft position sensor, Oxygen sensor, EGR valve, and evaporative system not working. The fuses for EMS1 and EMS2 and the main relay vary depending on what Aveo model you have. If...

Q: I have a Po171 code on a 2006 trailblazer

The cause behind diagnostic trouble code P0171 is easiest to find by looking at the secondary firing patterns on the Bank one cylinders. That will confirm if the too lean condition, that has caused the code to set, affects all...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.