Hi, here I'll post this for the person who have or will have a lean code like p0174 and others … the weak spot on all jaguar and land rover are these plastic vacuum line or pipe, they broke with the heat or crack because they become dry. so I'll post this to show you what / where and how to fix this problem while I fix it on my own XF.

-Right now I have this problem on my Xf, check engine is on, but other than that I haven't noticed any change in the car, it run fine.


Fix it by replacing the pipe crankcase breather. that's the pipe that go from a valve to the back of the throttle body. (picture to show)

What I did for now it's order my pipe from my jaguar dealer for about 52$
and I took off everything that was in my way,

next step is to take off the throttle body so I can get some space to work at the other end off the pipe.


here are some picture off what I did by now !

 

Excellent info sharing -- thank you!

As a DIY'er, I feel ready now for this code when it comes thanks to your post.

 

I had a lean code with my 2004 XJ VDP 4.2L. Found the cracking brittle hose connecting the crank case vent to the throttle body.


After unsnapping the hose from the engine, I carefully took a razor knife and cut the brittle hose way from the connectors. The ends of the connectors are barbed, so I took a piece of new rubber 5/8" ID heater hose from my tool box, pushed it on one end and cut to fit the length and pushed on the opposite end. Snapped my heavy duty hose in place. Looks like I saved $52.15, it is much more robust and seems to do the job.

 

Look at the picture that's what I did in the first place, but the hose sag so the car was running lean again. work for about a year or so than back to changing the hose again. so I decide to spend 52 $ to put back the original hose and decide to put some teflon wrap around.

the retail price is exactly 37.68$ 52 $ cause I had to got it shipped home

P.s the hose on the xj is way less longer than the one on the xf, so you are lucky cause it won't sag

 

I didn't realize that you were pointing to a previous fix. I will keep an eye on it. but since it is a much shorter straight length, maybe it will last longer.

 

so there it is the repair are finished !

I replace the crankcase breather hose and it was not as hard as I thought it will be once you unbolt the throttle body assembly and lift it you have enough room to work easily. To make sure the hose won't crack or dry with the heat of the engine I put some teflon wrap around the place where it touch the engine.

- I run the jag for two days now, did like 100 miles / km and the check engine is still off.

Here are some more picture to help you complete the job !