Which component signals potential major non-compliance when missing?

• A. A missing catalytic converter
• B. A missing catalytic converter or missing sensors.
• C. A missing EVAP line
• D. A missing exhaust hanger

Answer: (B)

Emissions control relies on components that either reduce pollutants or monitor the system. If the catalytic converter is missing, there’s no catalyst to convert harmful exhaust gases, so the vehicle cannot meet emissions standards. If sensors are missing, the onboard monitoring system has no data to verify proper operation, making it impossible to prove the system is controlling emissions correctly. These situations directly undermine the emission-control system, signaling major non-compliance.

Missing an EVAP line or an exhaust hanger is more about leaks or physical support than the core emissions-control function, so they don’t indicate major non-compliance as strongly. That’s why the option mentioning either a missing catalytic converter or missing sensors is the best choice.