What is the EGR valve on a Mercury Mountaineer?
What is the EGR valve on a Mercury Mountaineer? They are the EGR Valve, Differential Pressure Sensor, and the Actuator Solenoid. P0401 is a general code, which means that regardless of the year (1996+ anyway) and the model, it’ll have the same meaning regardless of which manufacturer built the vehicle (Mercury Mountaineer or not). How to test the EGR valve on a Jeep Wrangler? Test the EGR Valve- A vacuum gauge will help you determine if the EGR valve itself has gone bad. Here’s an article from Autozone on how to test it with a vacuum gauge. Testing your EGR...