Hi,

I have p04f8 code for chevy blazer (2022, 2.0L turbo). A dealer told me that there is moisture frozen on the crankcase pressure sensor in cold weather. This is a common issue for Blazer, needs to be replaced or cleaned up. Any one know where is the sensor located? I wants DIY to save $600 from the dealer. The sensor costs less than $20.

Thanks,

Nanguo

 

If my google skills are working properly, I believe the code is P04FB as detailed in PIP5841A. It looks like a fairly straight forward removal and reassembly, but I am having some trouble finding some actual underhood pictures of the process to share with you. The sensor itself is located in the PCV (positive crankcase ventilation) hose assembly (GM part number 12718937) and is pictured below:


The pressure sensor is the part bolted on to the hose assembly on the top left of the picture above. This assembly should be located on the driver side of the engine under the trim cover towards the back.

Your best bet would likely be to remove the entire PCV hose assembly by removing the two bolts at either end and taking it into someplace warm to thaw it out and then dry it with some compressed air.

As you stated, this entire assembly new is just over $20 as shown in the link above so if you chose to replace it rather than simply thawing out and cleaning your current one, it won't hit your wallet all that hard.

 

Thank you very much, I will check it out after work.

 

I am having the same issue with my Blazer 2022. Did you locate the part and solve the issue? Please keep us posted. Thanks a lot!
swartlkk: Thank you so much for the information!

 

If/when either of you go through with this repair, please take pictures of the process and post them for others to benefit! Thanks!

 

No, I haven't work on it yet as the engine light went off by itself.

 

Likely got warm enough underhood to melt the moisture that was froze over the sensor. It might not come back for a while if you have recently done some long distance driving to clear any builtup moisture from the system. A good long drive while it is warmer out might be the ticket to clearing this up as well.

 

I took a look under the hood of the Blazer and attached a few pictures for reference. I’m still unsure where the hose/sensor assembly is located.

Swartlkk, are you suggesting that I might not need to take any action to resolve this issue? Just wait for warmer weather and drive it for a while?

By the way, I’ve already reset the code using an OBDII reader. Thanks!

 

I'm not sure if I can see it in the lower picture just to the right of the rounded corner of the engine cover or not. You may need to remove the engine cover and take some more pictures of that side of the engine (similar to the 2nd picture you posted in terms of area).

If the code has gone away, then the condition that set the code has also gone away (i.e. the frozen moisture is no longer impacting the performance of the sensor). Can it come back, possibly. Cleaning this pipe is what the PIP details.

Circled in red could possibly be the connection shown on the right side of the picture I posted in my first reply to this thread.

 

Thanks for pointing this out! It does seem like it's the right part. I'll take another look/picture later today when I get a chance and will report back. Thanks again, Swartlkk!

By the way, do you have any tips or tricks for removing the engine cover? I don't want to brick the plastic considering it is below zero in the garage.