Error code

OBD2 P0407

OBD2P0407
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Exhaust Gas Recirculation Sensor 'B' Circuit Low.

Severity

moderateCan drive, but performance issues may occur.

Summary

P0407 indicates an abnormally low input voltage in the control circuit of the EGR valve's position sensor B. This sensor is typically located on or near the inlet manifold.

Symptoms

  • Check engine light illuminated
  • Engine may run rough, especially under load

Common Causes

  • Damaged wiring or connectors in the EGR system
  • Defective vacuum hoses (for vacuum-operated systems)
  • Faulty electrical control solenoid or stepper motor
  • Carbon buildup restricting EGR valve movement
  • Failed EGR valve position sensor

Diagnosis

  1. Inspect wiring and connectors for damage or corrosion
  2. Check vacuum hoses (if applicable) for splits or leaks
  3. Test electrical control solenoid or stepper motor
  4. Clean carbon buildup from EGR valve passages

Fixes

  • Replace faulty EGR position sensor B

FAQ

What causes P0407?

Common causes include damaged wiring, carbon buildup on the EGR valve, or a faulty position sensor.

Is it safe to drive with P0407?

It is generally drivable but may experience performance issues such as rough running under load.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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