P0400
Sistema
Powertrain (Emissions)
Escáner necesario
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Exhaust Gas Recirculation Flow Malfunction

Understand P0400, common causes, and the right FOXWELL scanner to diagnose it.

General EGR system fault — flow detected when none expected or control circuit issue.

Síntomas habituales

  • Rough idle
  • Knock under acceleration
  • Check engine light

Causas típicas

  • Failed EGR valve
  • Carbon blockage
  • Vacuum supply to EGR solenoid
  • DPFE/MAP sensor on Ford EGR

¿Qué escáner necesita?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Use datos en vivo y freeze frame antes de cambiar piezas. Códigos ABS, SRS y U suelen requerir un escáner de todos los sistemas.

Consejos de diagnóstico

  • Registre el freeze frame cuando se active el código
  • Borre el código solo tras corregir la causa
  • Revise códigos pendientes relacionados
  • Verifique que la batería esté por encima de 12,4 V antes de sospechar sensores

Escáneres FOXWELL recomendados

Preguntas frecuentes

Can I diagnose P0400 with a basic code reader?
P0400 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0400?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.