P0407 Fault Code

Exhaust Gas Recirculation Sensor B Circuit Low

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0407 code indicates that the Exhaust Gas Recirculation (EGR) Sensor B Circuit is experiencing a low voltage signal. This is a critical issue as the EGR system helps reduce nitrogen oxide emissions from the engine, which is vital for meeting environmental regulations and maintaining optimal engine performance.

What are the symptoms of the P0407 code?

Common symptoms associated with a P0407 code include:

• Check Engine Light illumination
• Rough idling or stalling of the engine during operation
• Increased emissions and reduced engine performance
• Decreased fuel efficiency
• Potential overheating due to improper air-fuel mixture.

What causes the P0407 code?

Several factors can contribute to this fault code, including:

• A faulty EGR sensor B
• Wiring issues such as shorts, frayed wires, or poor connections in the sensor circuit
• Malfunctioning EGR valve operation due to carbon buildup
• Issues with the Engine Control Module (ECM) that may not be sending the correct voltage
• Vacuums leaks in the system that affect the sensor's readings.

How to fix P0407?

To resolve the P0407 fault code, consider the following steps:

1. Inspect the EGR sensor B wiring and connectors for any signs of damage or corrosion.
2. Test the EGR sensor B for proper voltage and functionality using a multimeter.
3. Clean or replace the EGR valve if carbon buildup is found.
4. Ensure that the ECM is functioning correctly, and update or reprogram it if necessary.
5. Clear the fault codes and conduct a test drive to see if the issue reoccurs.