hello everyone. im having an issue on a xf 2.0 turbo that i just cant figure out. i have two codes that keep popping up after the first drive.

codes are P144c - Evaporative emission system purge flow performance during boost
and P0420 - catalyst system efficiency below threshold (bank 1)

ive replaced the EVAP purge valve twice now with Jaguar parts and i get the code back every time
i did a bench test on both valvs and the stock one to test the flow both under vacuum and under boost
as far as i could tell, all 3 worked as they should
the code will not set or be under a pending status if the vehicle is stationery.
ill rev the engine and get it into some boost and also brake boost it to get the turbo to spool up
no code pops up
as soon as i get on the road and it produces more than 5ish psi of boost, the code (P144C) will pop up and in a pending status
ill let is sit for a cool down period (about 2 hours) and then start it back up
code is still pending and no check engine light on in dash
go drive it around some more once it reaches operating temp
no code for the first 30-45min
after that, the code request CEL
P144C is set as a current code
drive around some more and monitor data
return to shop and turn the vehicle off. let it sit as i view the data from the drive
after about an hour i turn the vehicle on and the p0420 code is pending

im really stumped on this one because im not getting anywhere with any test or data that i view

we have already installed a new ECM and have the most current update in software available as well

i also reset the fuel trims because i wasnt sure if the company we had progam the ECM did that as it calls for it when reflashed

issue still remains and code keeps returning along with the 0420 code

anyone else come across this stubborn code? or if you have ever had this code and where able to fix it, what was your remedy to this?
im open to any suggestions or help to get to the cause of this.

thank you guys in advance and have a great day

 

Hello i have xe and i get same code interesting you found a solution to the problem.

 

It's interesting as I have the same code P0420 Catalyst System efficiency below threshold (Bank 1) - but I've got only this one. The funny think is that I can clear the code but all the time after 3-4 days fault is popping up again. Car is running normally, I didn't spot any performance loss etc.

 

The code is likely correct and the car is not actually running normally.

 

For sure You are right, but any idea what needs to be done?