Refractory P051b

[Drswiger]

2018 with 75K miles
Just replaced leaky water pump
Put the 75 pipes back to together and got a P051b, crank case pressure code after scanning the CEL
Well, changed the sensor and tube, changed the PCV valve and did a fresh oil change and CEL returns and same code scanned, P051b
What am I missing? Truck seems to be running ok. Can’t detect and excess pressure
I do have a JLT catch can but this has been installed for 5 years
Any help on where else I need to look

 

[FordTechOne]

Double check all of your connections. Do you have an aftermarket intake? That’s a common cause of that DTC.

 

[Drswiger]

I do have a COBB intake and COBB front mounted intercooler but both have been in place for 5 years

 

[FordTechOne]

Check all of the air cleaner and charge piping for any leaks; the best method is a smoke machine if you have access to one. Also check the o-rings in the PCV hose to ensure they’re not rolled/torn. If you have access to ForScan, monitor the CRNKCAS_P_V PID; the voltage should be 3.6-4.3V, if it’s out of spec you may have a circuit issue.