CUSTOMER CONCERN After cylinder-head gasket service, DTC P0016 sets. CAUSE Camshaft timing was misaligned after engine reassembly. CORRECTION Reset the camshaft timing to specification, clear DTC P0016, and verify proper cam/crank correlation and engine operation.

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.