Originally Posted by Snuggles.bf
The original Code was DTC P0401 = "EGR Flow Snsufficient" than a little bit down it says, "Mil REQUESTED, Since IGN NOT RUN, Since Clear P/F" so what exactly does that interput into? Thanks,
Basically, the PCM runs a test on the EGR system during deceleration by momentarily commanding the EGR valve open and comparing to the MAP input. So maybe there is still a problem with your EGR valve. That is what the DTC P0401 indicates, insufficient EGR flow. "MIL" Requested is the actual check engine light on the instrument cluster being requested by the PCM. If you feel confident that the EGR valve is functioning correctly, disconnect the battery for a few minutes then reconnect. If the EGR is not at fault, the DTC shouldn't set again.