Description
OBD-II Trouble Code Description for P0401 GMC
Exhaust Gas Recirculation Flow Insufficient Detected
What does this mean?
OBD2 Code P0401 GM definition:
EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 GM code means that OBD detected an insufficient amount of EGR.
Symptoms
Possible sumptoms of OBD code P0401 GM
You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.
Causes
Possible causes of OBD code P0401 GM
A code P0401 GM most likely means one or more of the following has happened: ?The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced ?There is a blockage in the EGR (tube), most likely carbon buildup ?The EGR valve is faulty ?The EGR valve may not be opening due to a lack of vaccuum
Possible Solutions
In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit. ?Use a vacuum pump and pull the EGR valve open while monitoring engine RPM’s & DPFE voltage. There should be a noticable difference in RPM’s with the EGR open ?Clean out the EGR valve and/or tubing to remove deposits ?Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model) ?Replace the DPFE sensor (with a good quality / OEM one) ?Replace the EGR valve
The OBD2 Code Information Be Applicable For GMC:
2013 GMC Terrain Denali,2013 GMC Acadia,2011 GMC Sierra All Terrain HD Concept,2010 GMC Terrain,2010 GMC Granite Concept,2009 GMC Sierra Hybrid Crew Cab,2008 GMC Yukon Hybrid,2008 GMC Denali XT Concept,2007 GMC Yukon XL,2007 GMC Yukon Denali,2007 GMC Yukon,2007 GMC Sierra Denali,2007 GMC Sierra Classic,2007 GMC Sierra 3500 HD SLT Crew Cab,2007 GMC Sierra 2500 HD SLT Extended Cab,2007 GMC Sierra,2007 GMC Acadia,2005 GMC Sierra Denali 1500 Crew Cab,2005 GMC Graphyte Concept,2005 GMC Envoy XL Denali,2005 GMC Envoy Denali
Note:
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