Error code P0016
 

2007 HHR, 2.2, 115,000 miles. Engine light came on one month ago, engine had rough idle after warming up, dont remember the code number but message was bad timing chain tensioner. Changed tensioner and ran fine till yesterday.
Engine light came on, engine did like it was going to cut out, but picked right back up. Engine stopped at stop sign, but started right up, but was shifting hard while shifting or downshifting, and going from park to drive. Stopped the engine for 5 minutes, restarted and ran fine driving home (30 minutes). Checked codes today, P0016, Crankshaft, camshaft position correlation. Six months ago, I changed the timing chain on the car, was running fine until recently. At this point, is there any way to know which sensor is bad or should I go ahead and change both, or look elsewhere for problem? Cleared codes this am, and threw same code within 5 minutes.

quote; "dont remember the code number but message was bad timing chain tensioner."

I don't recall a trouble code for a timing chain tensioner. Are you sure about this? And where did this "message" appear?

Mitchell OnDemand says:

A: Check the torque of the Crankshaft Balancer bolt
B:Inspect for correct installation of the CMP sensor INTAKE
C: Inspect the engine for correct valve timing (timing chain, sprocket, and tensioner)

If you do a search for p0016, I'll bet you get 20 results on this forum.

I was out of town, so didn't have my code reader with me. The codes were read at Advanced Auto Parts. Don't remember the exact message, but the suggestion was to replace the chain tensioner. I think there are 2 tensioners on the engine, 1 internal and 1 external. Changed the external one (rear of the engine passenger side against the fire wall) and car ran fine for a month. Local parts store only had crankshaft sensor available so picked it up last night. Will change it this am and see if that helps. The way it does, leads me to think it is something electrical, especially letting it cool down and restart, runs fine for a while.

The CMP sensor is the black one that lives on the front driver side of the head, between the oil filler & oil filter.

Only one tensioner, but guides wear out and do something toward tensioning the chain.