P0407
EGR Sensor B Circuit Low
P0407 is an OBD-II diagnostic trouble code meaning: EGR Sensor B Circuit Low. Common causes: egr sensor wiring short to ground, sensor power supply circuit open. Estimated repair cost: $6–133.
Symptoms
- Check Engine light is on
- Reduced fuel efficiency
- Detonation under load
- Unstable idle
- Increased exhaust toxicity
- Possible emergency operation of the engine
Causes
- EGR sensor wiring short to ground
- Sensor power supply circuit open
- Faulty EGR valve position sensor B
- Oxidation or damage to the sensor connector
- EGR valve dirty or stuck
- ECU malfunction (extremely rare)
How to Fix
- Connect the diagnostic scanner and read all active codes
- Check the sensor supply voltage (usually 5 V from the ECU)
- Check the sensor ground wire for integrity
- Inspect the connector and wiring harness for damage.
- Measure the sensor resistance and compare with the norm
- Replace EGR sensor B if its malfunction is confirmed
- Reset the error code and take a test drive
Related codes
Error P0407 by Vehicle Brand
FAQ
What does the P0407 code mean?
P0407 is an OBD-II diagnostic trouble code that indicates: EGR Sensor B Circuit Low
What causes a P0407 error code?
The most common causes of P0407 include: EGR sensor wiring short to ground; Sensor power supply circuit open; Faulty EGR valve position sensor B; Oxidation or damage to the sensor connector.
How do I fix a P0407 diagnostic trouble code?
To fix P0407: Connect the diagnostic scanner and read all active codes. Check the sensor supply voltage (usually 5 V from the ECU). Check the sensor ground wire for integrity. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P0407?
Do not drive — repair immediately
How much does it cost to fix P0407?
The estimated repair cost for P0407 is $6–133. Actual cost depends on your vehicle, location, and labor rates.
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