My 2009 Chevy HHR has been showing a p0016 and p0017 for 4 years now with no noticeable effect on engine performance. I’ve replaced the cam shaft position sensors and the actuators.it did have 2 exhaust actuators, I discovered, when I checked. I replaced them(so it had 2 exhaust ones for AT LEAST 4 years before discovery. Probably much longer) with the correct ones. After the sensors were replaced, it continued the 2 codes. It does take two turns of the key to start it, but I think that’s an anti drain back issues with my fuel system. When it starts and when running, there is no unusual noice. No slapping metal or clacking. It’s idle is a little rough, but not much and after 4 years of the engine light with the same codes, is it really the timing chain or could it be something as simple as a tune up? I don’t think it’s the timing chain itself but my mechanic at the time was at a loss for why changing the sensors didn’t fix the code. I’ve had it since 2015 and I’m guessing it’s got the original parts like battery and spark plugs. Any thoughts on what else could be triggering a cam shaft position issues on both banks?
Start by changing the battery and see how it goes.I would replace the spark plugs if they show deterioration.