Q&A

 Master

The definition for both codes are below i would reset the codes and check to see which one comes up first, if you get the p0401 i would check for a broken air line connected to the EGR, if you get get the other code the EGR might be stuck open i would get a local mechanic to test the EGR With a scantool it might be the EGR opening valve if so your in luck.

P0402 - Ford Type Powertrain - Auxiliary Emission Controls - ISO/SAE Controlled
Description

EGR Excessive Flow Detected Conditions
Cause

Engine running at idle speed (closed loop), then the PCM detected that the signal from the DPFE sensor indicated undesired EGR gas flow (idle speed fault).

P0401 - Ford Type Powertrain - Auxiliary Emission Controls - ISO/SAE Controlled
Description

EGR Insufficient Flow Detected Conditions
Cause

Engine running in steady state driving conditions (closed loop), then the PCM detected that the signal from the DPFE sensor indicated insufficient EGR gas flow.

 Master

dpfe is the most common failure.

Roy

 Rookie

google the codes...they will tell you