What does the error code P1401 mean on a 2001 Ford F150 V6?

The error code P1401 on a 2001 Ford F150 V6 indicates an issue with the EGR (Exhaust Gas Recirculation) system, specifically related to the EGR flow being insufficient or not detected. This can be caused by a faulty EGR valve, clogged passages, or issues with the EGR temperature sensor. Addressing this code typically involves inspecting the EGR components and ensuring proper function and airflow. Ignoring it can lead to increased emissions and reduced engine performance.