Engine code P0401 is a Diagnostic Trouble Code (DTC) that stands for “Exhaust Gas Recirculation (EGR) Flow Insufficient Detected.” This code is part of the On-Board Diagnostics II (OBD-II) system, which monitors your vehicle’s performance to ensure it meets emission standards and operates efficiently.
To understand P0401, knowing what the EGR system does is important. The Exhaust Gas Recirculation
system is designed to reduce nitrogen oxide (NOx) emissions by recirculating some exhaust gases back into the engine’s intake manifold. This process
lowers combustion temperatures and helps control emissions.