OBD-II code · Powertrain (generic)

P0407 EGR Sensor B Circuit Low

The signal from EGR position or pressure sensor B is below the lower diagnostic threshold. Indicates a short to ground, open signal wire or sensor fault.

Is it safe to drive with P0407?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyEGR sensor B internally faulty
  • PossibleSignal wire shorted to ground
  • Less likelyConnector corroded

Symptoms

  • Check engine light on
  • Pinging or knocking under load
  • Power loss and hesitation
  • Possible rough idle
  • Failed emissions inspection (NOx)

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
0.5–2 h
Emissions test
Likely to fail
Parts involved
Egr Position Sensor, Egr Pressure Sensor, Sensor Wiring

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.