Possible causes
– EGR passage clogged
– Faulty EGR Valve
– EGR solenoid valve harness is open or shorted
– EGR solenoid valve circuit poor electrical connection
– 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 obd code mean?
The Powertrain Control Module (PCM) sets a DTC P0401 when the fail counter exceeds the fail threshold. The number of test samples required to exceed the fail threshold varies according to the magnitude of the detected flow errors.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Possible engine hesitation
– Possible engine hesitation
P0401 GMC OBD Code Description