OBD-II DTC · SAE J2012

P0400

Exhaust Gas Recirculation Flow Malfunction

EGR → Suppressible (off-road only)

What P0400 means

P0400 is a standard SAE J2012 powertrain diagnostic trouble code with the defined meaning: Exhaust Gas Recirculation Flow Malfunction. This is the OEM-agnostic definition; specific manufacturer interpretation may add detail (subsystem, bank, sensor location) but the core meaning is consistent across all OBD-II compliant vehicles since 1996.

Can this code be suppressed via ECU tuning?

Very common service. EGR mechanical failure (sticking, carbon buildup) often pairs with ECU-side EGR off. Off-road or motorsport only.

Related codes in the P04xx family

P0401P0402P0403P0404P0405P0406P0407P0408P0409P0410P0411P0412

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