Cadillac STS Forum - 2005 through 2012 Discussion, 05 STS with 4.6. P0174 Lean bank 2 Fixed in Past Cadillac Vehicle Discussion; Just thought I would post this fix incase others are having similar problems. My car has around 90k on it ...
Just thought I would post this fix incase others are having similar problems. My car has around 90k on it and a couple days ago I got a CEL. I went looking for vacuum leaks since that's the easiest thing to cause a lean code. I found that the rubber ends on the vacuum pipe that goes from the passenger side valve cover to the rear of the intake manifold were totally disintegrated. the Pipe is 3/8 and I had some fuel line laying around so I just cut a piece for either end and replaced it. Getting the hose off the back of the intake is a challenge but doable. Hope this helps someone, I have to figure that everyone with the N* will run into this at some point.
PCV dirty air line connector breaks are common across the Northstar line. If necessary, that entire line can be replaced with a length of proper ID fuel line - fuel line has a reinforcing braid molded in.
Any of the other preformed plastic vacuum pipes and connectors may be replaced with lengths of proper ID vacuum hose from the Help! racks at parts stores.
Thanks for the feedback. P 017X codes are usually vacuum leaks - they show up as "lean mixture codes".