When should a catalytic converter be replaced according to the 550 rule?

The correct answer is based on the 550 rule, which specifies that a catalytic converter should typically be replaced every 5 years or after the vehicle has accumulated 50,000 miles, whichever comes first. This guideline is designed to ensure that the catalytic converter continues to function effectively in reducing harmful emissions produced by the vehicle's engine. Over time, catalytic converters can become less efficient due to wear, contaminants, and the accumulation of unburned fuel, which can lead to increased emissions and potential engine performance issues. Therefore, adhering to this replacement schedule is crucial for maintaining the vehicle's compliance with emission standards and overall functionality.