2012 GMC Terrain Engine rattle noise on start up, cold start, Stretched timing chain, Timing codes

Customer was concerned about engine rattle noise and check engine light is on. Scanned for codes and found P0016, P0017 crankshaft to camshaft correlation. Let the vehicle sit overnight and then confirmed a timing chain rattle coming from the front cover. Suspect stretched timing chain. Recommending a chaining time set with tensioner.