smoking Cadillac CTS 2003
 

Car is smoking badly under from the hood and there is nothing showing on the display of warnings

Most likely the valve cover gaskets.
 

The 3.2 Ellesmere engine is notorious for a poor PVC system design. This causes pressure to build in the engine and the weakest link is the plastic valve covers. There is a tsb to modify the system to reduce oil leakage. The problem is worse in cold climates as the system plugs with ice.