P0407

EGR Sensor B Circuit Low

Q: Is it safe to drive with P0407?

Generally yes. It's an emissions-related fault, so you may see slightly rougher running, but it doesn't stop the engine from starting. Repair it to pass emissions and keep EGR working properly.

Q: Can I just clear P0407?

It will return until the sensor or its circuit is repaired, and the car will not pass an emissions test with it pending.

EGR / emissions Generic OBD-II Medium

What it means

P0407 means the signal from EGR sensor B is reading below its valid range. This sensor reports how far the exhaust gas recirculation valve is open (or its temperature), letting the computer control EGR flow for lower emissions. A low signal usually points to the sensor, its wiring, or a poor connection, and mainly affects emissions rather than the ability to start or drive.

Medium

Can I keep driving? You can keep driving. You may notice slightly rough idle or hesitation, but this emissions-circuit code won't cause a no-start.

Real-world scan data

Seen in

110

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Slightly rough idle or minor hesitation
Reduced fuel efficiency
Failed emissions test

Common causes

Most likely first

Faulty EGR position/temperature sensor B (signal reading low)Likely
Wiring shorted to ground or an open in the signal circuitCommon
Corroded or loose sensor connectorCommon
Failed ECM (rare — check the sensor and wiring first)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and confirm the fault is on the EGR 'B' sensor circuit.
Inspect the sensor connector and wiring for a short to ground, corrosion, or loose pins.
Check the sensor's reference voltage and ground back to the ECM.
Measure the sensor's output and compare it against spec across its range.
Replace the EGR sensor if its signal stays low, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0407?+

Generally yes. It's an emissions-related fault, so you may see slightly rougher running, but it doesn't stop the engine from starting. Repair it to pass emissions and keep EGR working properly.

Can I just clear P0407?+

It will return until the sensor or its circuit is repaired, and the car will not pass an emissions test with it pending.

Read & clear P0407 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX