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P0407 Powertrain

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.

Affected components

  • Egr position sensor
  • Egr pressure sensor
  • Sensor wiring

Common causes

  • High likelihood: EGR sensor B internally faulty
  • Medium likelihood: Signal wire shorted to ground
  • Low likelihood: Connector corroded

Possible symptoms

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

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • This code can affect emissions

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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