Detection Condition
WARNING: This page is about a different car, the 2002 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
DTC P1400 indicates average voltage of DPFEGR SIG circuit input is less than the minimum of 0.2 volts.
DTC P1401 indicates average voltage of DPFEGR SIG circuit input is more than the maximum of 4.5 volts.
Differential Pressure Feedback EGR (DPFEGR) sensor measures the actual pressure drop across the metering orifice and relays a proportional voltage signal to PCM.