DTC P0404 Exhaust Gas Recirculation Circuit Range/Performance

In the intricate world of automotive diagnostics, grasping the significance of On-Board Diagnostic Trouble Codes (DTCs) is essential. Today, we shift our focus to DTC P0404, specifically the Exhaust Gas Recirculation (EGR) Circuit Range/Performance issue. In this comprehensive guide, we will unravel the meaning behind P0404, explore its potential root causes, investigate the symptoms associated with this trouble code, outline a systematic diagnostic approach, and provide effective solutions for resolving this concern. Let’s embark on a journey to uncover the intricacies of DTC P0404.

1. What Does P0404 Code Mean?

DTC P0404 is a diagnostic trouble code that signifies a range or performance problem within the Exhaust Gas Recirculation (EGR) circuit. The EGR system plays a pivotal role in reducing emissions by recirculating a portion of exhaust gases back into the engine’s combustion chambers. When a range or performance issue is detected, the Engine Control Module (ECM) triggers the P0404 code, indicating an anomaly within the EGR circuit.

2. What Are the Causes of DTC P0404?

To effectively troubleshoot DTC P0404, it’s imperative to understand the potential triggers behind this code. The underlying causes may encompass:

  • Wiring issues, such as damaged or corroded connectors within the EGR circuit.
  • A malfunctioning EGR valve or position sensor.
  • Carbon deposits or blockages within the EGR passages that affect performance.
  • Malfunctions in the EGR vacuum control solenoid or related components.
  • In rare cases, ECM-related problems affecting EGR circuit control.

Identifying the primary cause is the initial step toward resolving this range or performance issue.

3. What Are the Symptoms of DTC P0404?

Recognizing the symptoms associated with DTC P0404 is vital for early detection. Common indicators of this issue include:

  • An illuminated check engine light (CEL) on the vehicle’s dashboard.
  • Potential engine performance issues, such as reduced power and responsiveness.
  • Elevated exhaust emissions, potentially leading to a failed emissions test.

Addressing these symptoms promptly is crucial to prevent further complications.

4. How to Diagnose DTC P0404?

Accurate diagnosis of DTC P0404 requires a systematic approach. Here’s a step-by-step guide:

If initial inspections and basic testing do not pinpoint the cause of DTC P0404, consider employing advanced diagnostic tools, such as an oscilloscope, to assess the EGR circuit more comprehensively.

5. How to Fix DTC P0404 Problem?

Once you’ve identified the underlying issue triggering DTC P0404, it’s time to address it effectively. Here are steps to consider:

  • Repair or replace any damaged wiring or connectors within the EGR circuit.
  • Replace the malfunctioning EGR valve, position sensor, or vacuum control solenoid if necessary.
  • Clear any carbon deposits or blockages within the EGR passages to restore proper flow.
  • Ensure proper electrical connections and clean any corroded connectors.
  • After completing repairs, clear the trouble code using your OBD-II scanner. This step is vital for resetting the check engine light and confirming that the problem has been successfully resolved.

Conduct a road test to confirm that the issue has been rectified and that the check engine light remains off.


In this comprehensive guide, we’ve delved into DTC P0404, the Exhaust Gas Recirculation (EGR) Circuit Range/Performance code. Understanding its significance, recognizing symptoms, identifying potential triggers, systematic diagnosis, and the importance of code clearing equips you with the knowledge to confidently address this issue. Whether you’re a devoted automotive enthusiast or a seasoned professional mechanic, resolving such problems not only ensures cleaner emissions but also enhances your automotive expertise. Here’s to smoother and more efficient travels on the road ahead!