2004 Xj8 P0174
 

This is driving me crazier than I already am.
Started getting P0174 codes a couple of months ago, replace the MAF sensor first then did a smoke test. Found the Throttle body linkage was leaking but nothing else.
Bought a refurb from ASi and that didn't fix it.

Starting checking the O2 sensors with Torque and get no data from O2 sensors 1 on either bank. I'm not sure if Torque can read them or if they are bad and are sending no data. I really have to doubt both sensors went since I can clear the code and it will not come back for 5 or more cycles.
The fuel trim Bank 2 short term keeps going up to 25%.

What is the easest way to manually check the O2 sensors and does anybody have any other ideas since there are no visable vacum leaks ?

Help !!

dmhippy
04 XJ8

PS I checked the bellows and no cracks

My first thought is an intake manifold gasket leak on the bottom side where you can't detect it, even with smoke. Reseal of the intake could fix it. I've had to do that before, a few times.

If you suspect the O2 sensor, you could switch the upstream sensors side to side and see if the Code switches to P0171.

Cheers,

Thanks for the help, ended up being the O2 sensor on bank 2.

Cool! Thanks for reporting back!

We like positive reinforcement. :icon_dance-twist:


Cheers,

Same issue
 

I have fixed everything including new nameless cat ,I have search everywhere no leaks .
could it be the throttlebody leak like stated above the linkage ?
My last bet is the 02 sensor which one should I change upper one or lower one? To fix this 0174

When you changed your sensor which one did you change? And also did your car act sluggish?

It ended up being the lower left sensor.