P0407Emissions
EGR Sensor B Circuit Low
P0407 means the PCM detected the EGR position sensor B circuit is reading low voltage, often a short to ground, a failed sensor, or a wiring fault.
🚗 Yes, but the EGR system may operate incorrectly, affecting emissions and drivability.
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🎯 Top Causes, Ranked by Likelihood
#1Faulty EGR position sensor B$80-$250
A failed sensor outputs low voltage.
#2Short to ground in sensor wiring$100-$250
A grounded signal wire pulls the circuit low.
#3Poor connector or corrosion$20-$100
A corroded connector creates a low reading.
#4Open reference or supply voltage$100-$250
A missing reference voltage drops the signal.
🩺 Common Symptoms
- Check engine light
- Rough idle
- Hesitation
- Failed emissions test
- Reduced performance
💰 Repair Cost: DIY vs Shop
📋 Free OBD2 Code Cheat Sheet
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🔧 How to Diagnose P0407
1Inspect the EGR sensor B connector and wiring
2Check the reference voltage and ground
3Measure the sensor signal voltage
4Replace the EGR position sensor if faulty
❓ Frequently Asked Questions
Can I drive with P0407?
Yes, but EGR operation may be off, affecting emissions. Repair it soon.
What does P0407 mean?
The EGR position sensor B circuit reads low voltage, usually a short to ground, a bad sensor, or a wiring fault.
How much to fix P0407?
A replacement position sensor is $80-$250, and wiring repairs run $100-$250.
🔗 Related Codes
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