EGR Valve Diagnosis – What you Need to Know
Most EGR valve diagnosis starts with a check engine light and a code reader. P0401 means insufficient EGR flow. P0400 means general EGR malfunction. P0402 means excessive flow. The real work is figuring out whether the valve is stuck, the passages are clogged, the sensor is lying, or the wiring is bad. This guide walks … Read more