No disrespect intended to any ASE mechanics out there, but I worked in the jobber auto parts business for about 13 years and only ever came across 2 or 3 mechanics I'd ever trust to a job that I just can't do myself. In case you still want to look and touch, it's located under the valve covers on the front of the cam journals.
Shouldn't have to take off a lot of hardware to access (valve covers, fuel rails, some of the belt drive accessories, a few other bits of hardware, but not the intake manifold). Posted the same reply in another thead, but this is my thread, so I thought I should post a follow up: Fixed my cam phaser noise with $.50 worth of springs from the hardware store and a couple hours of my time.
Bottom line: I understand the theory behind how the cam timing is varied using a solenoid, electronic controls and hydraulic pressure, but it must be purty involved to troubleshoot and repair the system.
I'm guessing unless you're a Class 1-A shadetree mechanic with lots of factory training/knowledge, I'd leave it to the dealer.
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