AutoCodes – Generic – P0407

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

Quick Answer

Early Exhaust Gas Recirculation (EGR) systems component's include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Common causes include Faulty EGR volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted. 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 volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted.
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.

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Code Popularity 48,048

How popular is this code, among other codes? Medium

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 18, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0407 Description

Early Exhaust Gas Recirculation (EGR) systems component's include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from the exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.

OBDII Code P0407 - Exhaust Gas Recirculation Sensor 'B' Circuit Low - AutoCodes.com — P0407 Code - Exhaust Gas Recirculation Sensor 'B' Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0407?

Faulty EGR volume control solenoid valve
Carbon built up on EGR valve
EGR volume control solenoid valve harness is open or shorted
EGR volume control solenoid valve circuit poor electrical connection
Faulty EGR temperature sensor and circuit

How to Fix the DTC P0407?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0407 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0407 code?

Need more information on how to fix the P0407 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0407 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P0407 Mercedes-Benz — Exhaust Gas Recirculation Sensor 'B' Circuit Low

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.