P0404 Code

What is a P0404 Code

Seeing a check engine light illuminate can be worrisome for many vehicle owners. Although the light is critical for making you aware of a potential issue with your vehicle’s functionality, it doesn’t pinpoint where the problem is occurring or how severe it is. The first step in solving these issues is connecting a scanner to your automobile’s onboard diagnostic (OBD) system to retrieve the diagnostic trouble code (DTC) that triggered the check engine light.

Regardless of your vehicle’s make or model, thousands of DTCs exist, each representing a specific issue. These codes are vital for helping vehicle owners determine whether their cars are safe to drive while allowing technicians to begin an accurate diagnosis of the cause. A P0404 code often indicates a potential problem with your car’s exhaust gas recirculation (EGR) system.


What Does a P0404 Code Mean?

The EGR system’s primary responsibility is to direct exhaust back into the engine cylinders to reduce nitrogen oxide (NOx) emissions and lower cylinder temperatures. The EGR valve’s feedback system communicates with your powertrain control module (PCM) to let it know if your valve is open, closed or partially closed at a given time, alerting you when a malfunction occurs.

When the PCM triggers a P0404 code, it stands for Exhaust Gas Recirculation Circuit Range/Performance. This alert means that the EGR valve is performing outside your vehicle’s parameters. More specifically, it could mean the valve is closed when it should be open or vice-versa.


Potential Causes of a P0404 Code

P0404 codes can appear on any vehicle make or model with an OBD system. Although the code does not specify the exact issue, it offers a technician or seasoned do-it-yourselfer guidance for performing an accurate diagnosis.

A single problem or a combination of issues can trigger a P0404 code, including:

  • A dirty or malfunctioning EGR valve
  • Grounded or shorted wiring
  • A faulty EGR position sensor
  • Damaged wiring or connection problems leading to the EGR sensor
  • Erratic movement in the EGR valve
  • Carbon buildup on the EGR valve
  • A problem with the PCM


P0404 Code Symptoms

An illuminated check engine light is the most obvious sign of a P0404 code. During an EGR problem’s early stages, there may be no evident signs of an issue aside from the check engine light. Several possible symptoms to look for while you’re operating your vehicle include:

  • Pinging on acceleration
  • Rough running and erratic idling
  • High NOx emissions
  • Possible stalling
  • Decreased fuel economy


Diagnosing a P0404 Code

When diagnosing a P0404 code, remember that many of the above symptoms could be from a separate underlying issue. Like other DTCs, you must rule out multiple problems before pinpointing the primary cause. Some of the common steps an experienced technician might take during a diagnosis include:

  • Ensuring no other codes are present: Scan your vehicle to check for additional DTCs. If P0404 is the only code showing, clear the code, perform a test drive and check to see if it reappears.
  • Evaluating the PCM’s freeze-frame data: The freeze-frame data can identify the engine conditions when your PCM initially triggered the code. This process can help determine whether the problem is with the EGR sensor or the valve itself.
  • Inspecting and cleaning the EGR valve: Check the EGR valve for any carbon buildup that prevents the valve from opening or closing. Cleaning the valve could be the only fix you need to remove the code.
  • Removing and examining the EGR sensor: Disconnect the sensor. Testing it manually can isolate a potential failure.


How to Fix Code P0404

Fixing any DTC code starts with a correct diagnosis. Because a dirty valve is one of the most frequent code triggers, you should begin with an inspection or cleaning before investing money in a new sensor or an entirely new valve. Some of the other repairs involved in fixing a P0404 code might include:

  • Repairing the open or shorted wiring leading to the sensor or connector.
  • Replacing the EGR position sensor.
  • Replacing the EGR valve.
  • Checking the PCM and updating the software if required.


How Much Does Code P0404 Cost to Fix?

Only a precise diagnosis can tell you the exact repair your vehicle needs to clear a P0404 code. Having a professional technician diagnose the problem ensures an accurate evaluation and detailed repair estimate. While the labor rates vary in most shops, you can typically expect to pay between $50 and $150 per hour for labor or diagnostics.

Some general estimates for parts replacement — including labor and parts — are:

  • EGR position sensor replacement: $100 to $200
  • EGR valve replacement: $250 to $500 


Choosing Hot Shot’s Secret Additives for Your Vehicle

Hot Shot’s Secret offers several fuel additives that can help prevent common vehicle issues and DTCs while increasing overall performance. Diesel Extreme and Everyday Diesel Treatment are scientifically proven formulas that can significantly slow down carbon buildup on a diesel engine’s EGR valve.

Feel free to connect with us online with questions or to request additional information.