An emission control system or component that has been disabled, even though it is present and properly connected to the vehicle.

• A. Tampered
• B. Modified
• C. Not Applicable
• D. Disconnected

Answer: (B)

The idea being tested is recognizing when an emissions control device is altered in its function but the hardware stays in place. If a component is still physically installed and connected but no longer operates as intended, that situation is best described as modified. The part hasn’t been removed or left unplugged, it’s simply been changed from its original, factory-dependent behavior. That’s why this option fits: the system is present and connected, yet its function has been disabled through some modification.

Disconnection would mean the part is no longer connected at all, not just disabled. Not applicable isn’t about a present system, and tampering usually implies an intent to defeat the system’s purpose, which can overlap with modification but the wording here centers on the device being altered in function while remaining in place.