P401 Code

[elerner]

I've been throwing a P401 code everyonce in a while. The list says a P401 is "EGR, insufficient flow". Does anyone know if this is measured by the EGR Valve or at the EGR Boost Sensor?

Thanks,

Evan

[99mx5]

It is measured by the boost sensor. You might want to check the little steel EGR pipe for clogs or check the boost sensor vacuum line for leaks.

[Tom @ Fast Forward]

Most likely cause is the SS tube from the EGR valve to the TBA. Probably needs to be cleaned.