P0401 GMC Exhaust Gas Recirculation Flow Insufficient

Possible causes – EGR passage clogged– Faulty EGR Valve– EGR solenoid valve harness is open or shorted– EGR solenoid valve circuit poor electrical connection Tech description EGR flow malfunction could be caused by a clogged EGR valve or EGR tube. Before replacing any parts try cleaning the EGR valve, tube and passages. When is the…