P0404: OBD-2 error code interpretation and solutions

Enter the error code and car brand

Vehicle engine and/or automatic transmission

Code: P0404 - Exhaust gas recirculation (EGR) system – range/performance problem

The P0404 fault code is a common OBD-II scanner code for vehicle brands such as Toyota, Renault, Kia, Skoda, Nissan, Hyundai, Volkswagen, Ford, Mercedes Benz, BMW, and others. It indicates that the Engine Control Module (ECM) has detected a problem with the exhaust gas recirculation (EGR) valve or sensor. If this code appears on your OBD-II scanner, it means that either the valve or sensor is operating outside the specified range, or their performance exceeds the defined specifications.

Causes of P0404 Code

The most common trigger for the P0404 code on an OBD-II scanner is:

Failure of the EGR valve (Exhaust Gas Recirculation system) to move from a specific position when commanded to close.
The position of the EGR valve is regulated by the ECM (Engine Control Module) via a sensor installed at the top of the valve. If an issue occurs with this valve, the system generates the corresponding code.
The movement of the EGR valve should be seamless and smooth, with no interruptions. If there are any disruptions, the vehicle’s ECM registers the corresponding code.
This issue may also occur if the EGR sensor exceeds the upper limit when the ECM commanded the EGR valve to open.

Symptoms of P0404 Error

There are several common signs to watch out for when encountering the DTC P0404:

As with many other faults, the check engine light will illuminate, and at this point, the code will be stored in the ECM memory.
You may notice that the engine experiences premature ignition during acceleration. This issue with the Exhaust Gas Recirculation system can often cause rough engine operation.
The engine may even stall or exhibit fluctuations if the ECM is unable to correctly determine the position of the EGR valve.

How to Diagnose DTC P0404?

It’s good to have a systematic approach that you can use to ensure the correct diagnosis and resolution of this code. By following these steps in order, you can avoid common mistakes that may arise when troubleshooting this code:

Ensure you record or document the freeze frame data from the OBD-II scanner.
Clear all engine codes from the scanner.
Take the vehicle for a test drive and rescan with the OBD-II scanner to ensure the P0404 code doesn’t return.
Check the EGR PID sensor on the scanner to determine if the sensor shows that the valve moves freely.
Remove the EGR sensor and manually operate it to determine if it’s the cause of the sensor or valve failure.
Remove and inspect the exhaust gas recirculation valve to ensure that carbon buildup is not obstructing its function. This can affect the accuracy of the sensor.

How to Avoid Common Mistakes with OBD Code P0404?

However, there are some common pitfalls that can occur when diagnosing and resolving the P0404 fault code. These pitfalls may include:

Failure to manually check the position of the EGR sensor. This can lead to confusion about whether the sensor or valve is faulty and may result in unnecessary replacement of functioning components.
Additionally, neglecting to check the wiring connections and cable bundle to the SRVG position sensor. It’s recommended to address these issues before replacing the SRVG valve or position sensor.

How Serious is the P0404 Error?

If the EGR system triggers this code, it can lead to the EGR control module being disabled, rendering the system faulty. If the check engine light remains on, this may result in the vehicle failing an emissions test. It’s important to note that proper functioning of the EGR valve is critical for the engine control module, as the system must efficiently manage its opening and closing.

How to Fix the P0404 Code?

This code can be resolved by replacing the stuck EGR valve, or if it cannot be cleaned, installing a new one. Also, consider replacing the EGR position sensor if it is found to provide incorrect data to the ECM (Engine Control Module), especially when manually moving it during diagnosis. Fix any shorts or breaks in the wiring to the EGR position connector or sensor.

Conclusion

This is a significant fault code that should be addressed as soon as possible, as in certain situations, it can lead to the failure of your vehicle. When resolving this issue, make sure to carefully follow the diagnostic steps.

Video for "Error p0404" on YouTube

The following error codes are often searched for

Comments on the article

OBD P0404 code analysis and solutions

The page presents a in-depth analysis of code P0404 for Opel, Renault, VW (Volkswagen), Ford, Peugeot, Mitsubishi, Skoda, BMW, Citroën, Toyota, Lada, Honda, Kia, and other models to investigate probable causes and solutions related to obd-ii errors, with emphasis on the issue. We offer technical descriptions and methods for diagnostics to identify and resolve the issue effectively. We aim to make our resource a comprehensive source of information on issues related to OBD 2 errors, equipping you with the means for effective repair and maintenance of your auto. If during the fixing of OBD2 codes you need to purchase parts, don’t forget to check out Avtopro!