CUSTOMER CONCERN The engine rattles during startup, misfires on all three bank-2 cylinders, and stores DTC P0021. CAUSE Camshaft timing was incorrect from a failed timing chain; a supporting confirmed report also documents worn guides and a camshaft actuator. CORRECTION Remove and replace the failed timing chain and related worn timing components, set camshaft timing to specification, clear DTC P0021 and the bank-2 misfire faults, and verify quiet startup and correct engine o

CUSTOMER CONCERN The engine runs rough with a timing-chain rattle and stores DTCs P0011 and P0300. CAUSE Diagnosis confirmed a worn timing chain as the source of the camshaft-timing fault, misfire, and rattle. CORRECTION Remove and replace the timing chain, clear DTCs, and verify smooth engine operation without timing-chain noise.

CUSTOMER CONCERN Engine runs rough at idle with DTCs P0016, P0089, and P228D, and the engine oil level is approximately three quarts low. CAUSE Inspection found the upper timing-chain guide failed, with the top of its bracket missing and grooves worn into the valve cover. CORRECTION Remove and replace the timing chain and correct the failed upper-guide condition.