P40DB Code after water pump replacement on Ecoboost 3.5

[darin]

I replaced a leaking water pump on a 2017 Explorer Sport with a 3.5 Ecoboost. Now it throws a P04DB - PCV Pressure sensor disconnected. Apparently it isn't seeing the appropriate pressure reading from the sensor in the PCV line and assumes the sensor or hose is disconnected. The engine seems to be running fine.

 I couldn't find anything disconnected and I replaced the PCV pressure sensor, which also comes with the pipe that goes from the front valve cover to a port on the plastic intake pipe. This didn't fix it. I tried replacing the PCV valve but that also did nothing. I don't see anything wrong with any of the air pipes or vacuum lines.

 Here's what is odd to me: The code sets immediately upon start-up, as a pending code. The car has to be started multiple times before the light will come on. It seems to me for that code to throw immediately it would have to be something electrical. It sets before there could be any build up of crank-case pressure to detect. Again, the pressure sensor is new (from Ford).


 Any ideas?
 
 Keep in mind, I did have to remove the intake manifold and both valve covers (along with the timing cover) to replace this water pump. 

[chippie]

It seems to me for that code to throw immediately it would have to be something electrical. It sets before there could be any build up of crank-case pressure to detect. Again, the pressure sensor is new (from Ford).

A thorough check of the wiring for the sensor would be my first...

[rhyds]

Hello and welcome

This is an UK forum and unfortunately we didn't get the 3.5 Ecoboost in the UK, so our specific knowledge may be limited

As chippie says check the actual wiring first, also check you haven't mixed up the pcv sensor connector with one for another circuit nearby

Also, check for an intake, vacuum or pcv system leak. Is live data showing pcv pressure as being low?

[darin]

The live data shows very little pressure registered by the sensor, but I don't know what is normal. The 3 wires to the sensor checked out.

 I didn't realize this was a UK oriented site, but thanks for taking the time to answer!

[chippie]

Nov 18, 2023 19:26:08 GMT 1 darin said:

The live data shows very little pressure registered by the sensor, but I don't know what is normal. The 3 wires to the sensor checked out.

 I didn't realize this was a UK oriented site, but thanks for taking the time to answer!

No pressure detected, I’d be checking the pipe work to the sensor then…as far back to the tapping point…

[Karl]

If I get time tomorrow I’ll check Ford PTS for known concerns

Might need something like a PCM update to latest calibration to suit new hardware

[valhalla]

Did you renew the gaskets under the valve-covers - seals between valve-covers and heads? Sounds like there may be an air-leak from the top of the engine. If you have a smoke leak-detector, it would speed things up to pump smoke back up the PCV line to the front valve-cover, and see if any escapes from the valve-cover seals.

[chippie]

I seem to think there was a similar thread with an air issue sometime back? Or is my mind playing tricks?..