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Engine-Codes – Generic – P0407

P0407 Code - Exhaust Gas Recirculation Sensor 'B' Circuit Low

Quick Answer

The P0407 diagnostic trouble code (DTC) indicates a problem with the Exhaust Gas Recirculation (EGR) sensor 'B' circuit being lower than the expected voltage range. Common causes include Faulty EGR Sensor: The most common cause of the P0407 code is a malfunctioning EGR sensor 'B', Wiring Issues: Damaged or corroded wiring connecting the EGR sensor to the ECM can cause circuit low voltage readings, EGR Valve Stuck Open: If the EGR valve is stuck open, it can affect the sensor readings and trigger the P0407 code. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P0407 indicates Exhaust Gas Recirculation Sensor 'B' Circuit Low.
Common causes
Common causes include Faulty EGR Sensor: The most common cause of the P0407 code is a malfunctioning EGR sensor 'B', Wiring Issues: Damaged or corroded wiring connecting the EGR sensor to the ECM can cause circuit low voltage readings, EGR Valve Stuck Open: If the EGR valve is stuck open, it can affect the sensor readings and trigger the P0407 code.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0407 Description

The P0407 diagnostic trouble code (DTC) indicates a problem with the Exhaust Gas Recirculation (EGR) sensor 'B' circuit being lower than the expected voltage range. The EGR system is responsible for reducing nitrogen oxide emissions by recirculating a portion of the exhaust gases back into the intake manifold to be re-burned. The EGR sensor 'B' is used to monitor the position of the EGR valve and provide feedback to the engine control module (ECM) to ensure proper operation.

OBDII Code P0407 - Exhaust Gas Recirculation Sensor 'B' Circuit Low
P0407 Code - Exhaust Gas Recirculation Sensor 'B' Circuit Low

Common Causes of P0407

  1. Faulty EGR Sensor: The most common cause of the P0407 code is a malfunctioning EGR sensor 'B'.
  2. Wiring Issues: Damaged or corroded wiring connecting the EGR sensor to the ECM can cause circuit low voltage readings.
  3. EGR Valve Stuck Open: If the EGR valve is stuck open, it can affect the sensor readings and trigger the P0407 code.
  4. ECM Malfunction: A malfunctioning ECM can also cause incorrect voltage readings from the EGR sensor 'B'.

Symptoms of P0407

  1. Check Engine Light: The most common symptom associated with the P0407 code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Fuel Efficiency: A malfunctioning EGR sensor can lead to decreased fuel efficiency as the engine may not be operating optimally.
  3. Rough Idling: The engine may experience rough idling or hesitation when the EGR system is not functioning correctly.
  4. Engine Stalling: In severe cases, the engine may stall due to improper exhaust gas recirculation.

How to Fix P0407

  1. Diagnose the Issue: Use a scan tool to verify the P0407 code and perform a visual inspection of the EGR sensor and wiring.
  2. Replace EGR Sensor: If the sensor is faulty, replace it with a new one following the manufacturer's guidelines.
  3. Check Wiring: Inspect the wiring for any damage or corrosion and repair or replace as necessary.
  4. Test EGR System: After repairs, test the EGR system to ensure proper operation and clear the DTC with a scan tool.

Cost to Fix P0407

The typical repair costs for addressing a P0407 code can vary depending on the specific vehicle make and model, as well as the location and labor rates of the auto repair shop. In general, replacing the EGR sensor 'B' and addressing any wiring issues can cost between $150 to $400 in parts and labor. It's recommended to consult with a local auto repair shop for a more accurate estimate based on your vehicle's requirements. Keep in mind that diagnostic time and labor rates can influence the overall cost of the repair.

When is the Code Detected?

An improper voltage signal is sent to ECM through the valve

Need more information about the P0407 code?

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Code P0407 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0407 Code

1. What are the common symptoms of OBDII code P0407 (Exhaust Gas Recirculation Sensor 'B' Circuit Low)?

- Common symptoms include engine hesitation, rough idling, decreased fuel efficiency, and the illumination of the Check Engine light.

2. What can cause OBDII code P0407 to trigger?

- This code is typically triggered by a faulty Exhaust Gas Recirculation (EGR) sensor 'B', damaged wiring or connectors related to the sensor, or a malfunctioning EGR valve.

3. How serious is OBDII code P0407?

- While the severity can vary, it is important to address this code promptly as it can lead to poor engine performance and increased emissions if left unresolved.

4. What are some possible DIY repair tips for OBDII code P0407?

- DIY repair tips include checking the wiring and connectors for damage, cleaning the EGR sensor 'B', and ensuring proper connection to the EGR valve.

5. Can driving with OBDII code P0407 unresolved cause further damage to the vehicle?

- Continuing to drive with this code unresolved can potentially lead to reduced engine efficiency, increased emissions, and long-term damage to engine components.

6. How can I prevent OBDII code P0407 from occurring in the future?

- Regular maintenance of the EGR system, including cleaning and inspection, can help prevent issues that may trigger this code.

7. Is it safe to drive my vehicle with the Check Engine light on due to code P0407?

- It is generally safe to drive the vehicle for a short distance with the Check Engine light on, but it is recommended to address the issue as soon as possible to prevent further problems.

8. How long does it typically take to repair OBDII code P0407?

- The repair time can vary depending on the exact cause of the code, but it may take anywhere from 30 minutes to a few hours to diagnose and fix the issue.

9. Will resetting the Check Engine light resolve OBDII code P0407?

- Resetting the light may temporarily turn it off, but if the underlying issue causing the code is not addressed, the light is likely to come back on.

10. Can a mechanic easily diagnose OBDII code P0407?

- A qualified mechanic can diagnose this code using a diagnostic scanner to retrieve the specific details of the fault and pinpoint the exact cause for repair.

1. What are the common symptoms of OBDII code P0407?

The common symptoms of OBDII code P0407 include poor engine performance, rough idling, decreased fuel efficiency, and the illumination of the Check Engine Light.

2. What does the OBDII code P0407 indicate?

OBDII code P0407 indicates a low voltage condition in the Exhaust Gas Recirculation (EGR) sensor 'B' circuit.

3. What are the possible causes of OBDII code P0407?

Possible causes of OBDII code P0407 include a faulty EGR sensor, damaged wiring or connectors in the EGR sensor circuit, or a problem with the EGR system itself.

4. How can I diagnose the cause of OBDII code P0407?

Diagnosing OBDII code P0407 involves inspecting the EGR sensor and its wiring for any visible damage, testing the sensor's voltage output, and checking the EGR system components for proper operation.

5. Can I continue driving with OBDII code P0407 present?

It is not recommended to continue driving with OBDII code P0407 present, as it can lead to further engine damage and decreased fuel efficiency.

6. How can I repair OBDII code P0407?

To repair OBDII code P0407, you may need to replace the faulty EGR sensor, repair any damaged wiring or connectors, or address any issues with the EGR system components.

7. Will resetting the Check Engine Light fix OBDII code P0407?

Simply resetting the Check Engine Light will not fix OBDII code P0407. The underlying issue causing the code needs to be diagnosed and repaired.

8. How much does it typically cost to repair OBDII code P0407?

The cost to repair OBDII code P0407 can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

9. Can a DIY enthusiast fix OBDII code P0407 at home?

Depending on their skill level and access to tools, a DIY enthusiast may be able to diagnose and repair OBDII code P0407 at home by following a repair manual or online guides.

10. How often does OBDII code P0407 occur in vehicles?

OBDII code P0407 is a relatively common issue in vehicles equipped with EGR systems, especially in older vehicles with higher mileage. Regular maintenance can help prevent this code from occurring.

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