Visual Inspection

MECHANICAL
Leaks Metal fatigue Pipes Catalytic converter Muffler(s) Joints Mountings Clearance around components Exhaust gas recirculation valve(s) Supercharger

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step
If the cause is not visually evident, check for diagnostic trouble codes (DTCs) and refer to the DTC index