Question

2007 F350 Diesel 6.0 super duty obd2 fault codes P0401, P0404, P1335 have not been able to find the discription for these codes??

Answer 1

P0401 EGR flow insufficient detected

Description

the EGR system is monitored during steady state driving conditions while the EGR is commanded on
the test fails when the signal from the differential pressure teedback EGR sensor indicates that EGr flow is less than the desired minimum

Possible causes

vacuum supply
EGR valve stuck closed
EGR valve leaks vacuum
EGR flow path restrited
EGRVR circuit shorted to PWR
VREF open to DPF EGR sensor
DREF EGR sensor downstream hose off or plugged
EGRVR circuit open to PCM
VPWR open to EGRVR solenoid
DPF EGR sensor hoses both off
DPF EGR sensor hoses reversed
damged EGR orifice tube
damaged EGRVR solenoid
damaged PCM