Check Engine light Error Code PO174
 

I have a 2004 Ford F-150 4.2 liter V6. Heritage 116000 miles. The check engine light went on last week. (Error Code PO174). Is this the PCV valve?. Should I replace this part right away? The truck idles and runs great. Any issues if not replaced soon?

Is that the only code, or is it accompanied by PO171?

https://www.autocodes.com/p0174_ford.html
and P0301?

here are the threads in this group on p0174 codes....enjoy

https://www.f150forum.com/search.php?searchid=15827167

The pcv is easy to check. Start her up and pull it out of the valve cover (leave it on the hose). If it has vacuum (sucks your thumb print into it) it's likely ok. There is an infamous elbow, part of the pcv system, under the throttle body that is notorious for developing a hole and causing codes. Cheap fix, if that is the problem. Good luck.

Thanks for the reply. I'll check it today.

Generally this scenario will produce PO171 and PO174 simultaneously, which is why I asked my unanswered question.

There are a lot of helpful people on here, but we are throwing darts if you can't answer the questions.

Check your pending codes. P0171 is probably there. Watch the trims when the engine is cold. That's probably when the code was set. It will show in freeze frame data too.

Isolator bolt grommet/gaskets get hard and fail pretty quickly, mile-wise. Mine went at 75,000.

It will run fine with no damage for quite a while like that. The problem you'll have though is that if more codes crop up you won't know about them, cause your light is already on.

Thanks for the reply. I'll check the rubber grommets. I'll also replace the PCV valve and see if the check engine light goes off.