Please be careful here, I don't want to misguide you. You are absolutely correct, P1400 is not the usual DTC
thrown for a failing DPFE
sensor. I don't remember which DTC
is. Someone on this forum should be able to say. P1400 is pretty specific. It says that the DPFE
voltage as measured at the PCM
is incorrect. There's a lot of equipment that can affect that measurement, for example, the analog-to-digital convertor in the PCM
, the wiring from the DPFE
sensor to the PCM
, the DPFE
sensor itself, grounds, or the V reference supply to the DPFE
sensor. A good visual inspection may reveal something. Some time spent with a digital volt meter (high input impedance) or a good scan tool that can interrogate the DPFE
would be helpful. Then again, the DPFE
sensor is notoriously unreliable.
Good luck. Let the forum know how it turns out. We all like to learn.