What does code p06dd mean on the 2014 chevy silverado?

On the 2014 Chevrolet Silverado, fault code P06DD indicates an issue with the engine oil pressure control solenoid valve. This can point to serious issues with the oil pump, but 2014 Silverado models are known to throw the code without meaningful defects. General Motors points to a technical service bulletin (PIP5407) if the code reoccurs after diagnosis and replacement of offending hardware. You can read more here -- https://static.nhtsa.gov/odi/tsbs/2016/SB-10080702-2280.pdf -- but the gist is that the tensioner spring in the timing chain guide may have an issue that won't allow it to fully seat into the guide pivot end. This leads to the cycling oil pump control valve not being able to cause changes in an oil pump response. They make some recommendations based on where to go next.