P0400: Exhaust Gas Recirculation Flow Malfunction
HighPowertrainEGR System
What does P0400 mean?
P0400 is a diagnostic trouble code indicating "Exhaust Gas Recirculation Flow Malfunction". A component in the egr system has been flagged as malfunctioning by the vehicle's ECU. This requires diagnosis to determine whether the part itself has failed or if there is a related wiring or control issue.
Common causes
- Faulty egr system component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
This is a significant issue that should be diagnosed and repaired soon. Avoid long trips or heavy driving until the problem is resolved. Continued driving may cause additional damage.
Get a diagnosis for YOUR car
Code P0400 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.