PO401, what does it mean?

I just bought a 99 Mercury Sable (same as Tarus) at an auction. It seems to run fine, everything works great, but after about 10 miles the service engine soon light came on. Nothing seemed to change in the way the car was running. When i got home I hooked up my scan guage2 to it and it said 3 codes stored. But I could only get PO0000 and then PO 401 no 3rd code. Does anybody know what those codes mean? Thanks a lot!

The PO0000 is not a valid code. Was it a P0000?

The P0401 is a generic code (same for any car sold in the US since 1996) and means "Continuous Memory Self-Test has detected insufficient EGR flow." This is likely due to a bad DPFE sensor or the hoses to it.

-Rod

The PO0000 is not a valid code. Was it a P0000?

The P0401 is a generic code (same for any car sold in the US since 1996) and means "Continuous Memory Self-Test has detected insufficient EGR flow." This is likely due to a bad DPFE sensor or the hoses to it.

-Rod
Thanks, it might have been P0000 I'll have to check again if the light comes back on since I reset it.

I don't see where P0000 is a valid code either. DTC P1000 indicates that all of the OBD II monitors have not yet been successfully tested.

-Rod

I would guess that the auction place, or the person bringing in the car, disconnected the battery and turned the key fully to start a couple of times to wipe out the codes. It will probably take a couple of days driving in various conditions for all the problems to show codes again. So drive it, pay attention to how it performs, then check the codes again.
Hey Shorod, did you get the new one, or just change your picture from the old engine?

Hey Shorod, did you get the new one, or just change your picture from the old engine?

I picked up a 2011 SHO last Friday, traded in my 2007 Infiniti G35 and so far don't regret it.

-Rod