This is only an emmisions issue and means only that a sensor has determined that the amount of Exhaust Gas Recirculation that is being introduced into your intake manifold via the EGR valveisn't quite enough. The vacuum or electrical valve that opens the EGR valve itself isn't quite working properly. Your vehicle should probably still be running OK ; check the EGR solenoid or vacuum connection for defects if possible.
2001 ford windstar has code PO401 erg insufficent flow.
I had the same thing happen to my car that code means insufficent egr flow. You have to replace the egr valve.
On a 2002 Ford Ranger : The Mass Air Flow Sensor is between the engine air filter and the engine air intake tube
Trouble code P0402 means:Exhaust gas recirculation flow excessive detected
My Chilton repair manual shows code P0402 as EGR flow at idle fault and my Haynes repair manual shows code P0402 as EGR excessive flow detected
The code depends on the manufacturer. Get it to autozone and have it tested, they will give you a printout of the most probable causes. What kind of car and engine is it? For a ford, p0401 insufficient flow within the egr system. it is most likely then a dpfe sensor or a clogged passage in the egr system. cheap fix.
DPFE sensor
Trouble code P0441 means: EVAP Purge Flow Monitor Fault
Trouble code P0401 means:Exhaust gas recirculation flow insufficient detected
P0401 = Insufficient EGR Flow
egr passage way in engine plugged with carbon. will off of engine, make sure egr is ok.
Trouble code P0441 means:Evaporative emission control system incorrect purge flow