Engine whining and pinging sound DTC P0327

2005 traiblazer 4wd I6 38k miles

About a month ago i was getting ready for work and went to warm up the truck as it is cold here in NH. When i cranked the engine i got a high pitched squeel sound that lasted like 5 or 10 seconds as the engine started and ran then the sound went away but ever since there seems to be an excessively loud tinging and whining sound coming under the hood anytime the engine is running, hot cold idling driving parked doesnt matter.
i checked the pulleys and steering fluid levels the serpentine belt and fan (the fan has slight movement as it spins)everything else looks to be spinning tight and not much movement, after getting my head under there today as it is almost above freezing finally, it sounds like the sound is two fold, the whirling/whining from the front end around the pulleys somewhere, the more annoying deeper sounding whine and ting coming internal to the engine not from the front end, although it is loud enough that it is hard to place.
The SES light came on the other day so today i hooked up an auto tap and got a P0327 code (knock sensor low voltage)? in history but there is is no present setting codes just the H code P0327 i would assume this is related?

The only other issues i ever had with this truck was an intermittent P0410 code about 4k miles ago (in august) just before the warranty ran out, the dealer replaced an O2 sensor, then same code in again a week later so they replaced the other O2 sensor code came back just after warranty ran out but went away on its own dont know if this is useful information or not but thougt i would put it out there

Any help would be great as i leave for work every morning at 0430 and im sure my neighbors are tired of hearing it warm up every day

The noise and the P0327 are probably NOT related. If the DTC is in the history file, the problem is not present. If you still hear the noise, that pretty much confirms they're not related.

Serpentine belts and pulleys can make the noises you're describing though, so you might want to investigate that. The squeel may be an indicator that the alternator is working hard to charge the battery. If the battery has a weak cell, that could be the problem.

Old_master Thanks for the information. however it presents me more questions than answers at this point

The problem is the DTC was a history but only from the other day as the light was still on, and now after i cleared the codes yesterday and the light went out it came back on again this morning and there is now a current DTC P0327 knock snsor ckt low voltage.. not being a mechanic by trade im not sure what that means entirely however using the autotap i have there is a knock sensor count, and voltage reader.. The KS voltage with ignition on and engine off runs 4.51 as soon as engine starts voltage jumps to about 4.88 then as the engine rpms come down the KS voltage indicates anywhere from 1.2 to 3.5 usually in the low to mid 1 range. not sure if that is low or not low but it is what it shows The KS count seems to run between 2 and 6.

As for the battery im getting a perfect 12 volts with engine off and running about 14.4 with engine running, the truck seems to start fine not like the battery is dead how can i tell if it is a cell like you said or the alternator straining?

Also while poking around the alternator and other pulleys i noticed a probably unrelated issue but i dont knwo if it is or not. The main fuse panel under the hood behind the battery.. There are 3 posts on the front end of it, 2 that are "connected per say" and a third one that is most inboard. The inboard one has no wires connected to itThere is a pretty heavy set of wires that goes into the bottom of the fuse panel and attaches to a harness that is inboard the fuse panel as well. Now i noticed a little red lead coming out of that set of wires that has a flat connector on it that is trimmed to the shape that is around the third post however it is not connected to anything it is just hanging in the engine compartment. Is there supposed to be anything connected to this inboard post, this wire is the perfect length and has a connector with edges trimmed like it should be connected there?
i have a picture but apparently dont know how to add one to a post?

i realize this is a long post but the more details i can give i hope the more help i can get..

I believe that wire is for the trailer harness, not an issue with your problem, there is something going on with the KS, looks like it could be bad, or you have enough internal engine noise to retard the timing. You may need a more comprehensive scan to look at the parameters more closely. Look for corrosion on the sensor connector or any other external issue in the area.

I cant tell about your codes but for that whining sound check your idler pulley. I have a 2005 trailblazer and had to have mine replaced 3x. I asked the tech at the dealership whats up and he told me its a ongoing problem with them.

Possible battery condition? I've heard 12 is low for off and should be 12.5-12.7? Just repeating knowledge.

I've gotten that squeal from time to time too, but it never persists...