2015 Suburban, P0172 & p0175

[Loki223]

Well recently picked up the suburban, dealer cleared the codes right before i bought her and low and behold, they came back. So partially documenting this to help others, but i welcome others to chime in as well. P0172 & P0175, from what i've looked into so far, it seems the common issue is High pressure fuel pump under the intake, or MAP sensor. With the map sensor generally being the culprit when it comes to running lean, but these are running rich. To truly verify, i'll need to warm her up and unplug the map and watch my fuel trim levels to see what they do, but i guess it's pretty common for the HPFP to leak internally and share it's fuel vapors into the intake, increasing the fuel air mixture and causing a rich AFM. I might diag a little bit tonight, but it is 100+ degrees today, so we will see.

Code list



And initial data pulled, on a cold engine after sitting for several days










Open to thoughts and opinions

 

[Loki223]

Out of curiosity, do people have a preference on replacement High pressure fuel pumps? seems like they are a common issue, so curious if there is a better then stock replacement?

 

[Loki223]

We did some diagnostics, and confirmed high pressure fuel pump is the issue. Buddy of mine used to be a mechanic and while there he walked around to the burb and reset a magnet in the HPFP which can be an issue on these. It worked for about 2 days before the codes came back, so problem is confirmed to be the fuel pump. Ordering a new one now. He mentioned on a lot of these engines resetting that magnet can fix the problem for months or years in his experience, he had a home made tool to do it, but i will try and find a video of someone else doing it to share for others to reference

 

[Loki223]

Alright, so being a 2015 my fuel pump is driven by a tappet, that's what failed. Still replaced the fuel pump, but there is the cause of these codes for my 2015. Had my buddy do the work since my garage is still being rebuilt. He had a spare tappet from a previous truck that he was able to use, cam still looked good, so this case is solved on the burb. Now to go through the rest of the deferred maintenance

 

[Loki223]

And should mention here since i'm talking in codes to myself, the P06DD was the oil pressure solenoid. We were able to swap it out by going in from the bottom but was a PITA, not gunna lie, would've been really nice of GM to have made this part a little more serviceable P/N is 12640667 but i think there is an updated P/N for it, had to have mine shipped in from Montana