I once had excessive and insufficient at the same time.. So I replaced the DPFE and for a week I was golden. Then excessive kept on popping up. So I replaced the EGR valve... So for about 2 weeks it works then CEL came on again for excessive. So the solenoid gets replacement.
The entire EGR system was replaced and still the EGR system was throwing CELs like no other.
So then I got an xcal 2 and turned the bugger off
Not having to worry about EGR is golden
