Some owners of 2013-2018 Cadillac XTS vehicles equipped with a 6-cylinder engine may comment on an exhaust smell and/or leak, with the MIL on. DTC P0430 and/or P0420 may be stored. This may be due to a crack around the catalytic converter mounting flange. If cracks re found, replace the converter.
The left side ASM-3way converter with exhaust pipe is available as P/N 84216836. The right side is P/N 84216838.