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CPT Emissions & Environmental Standards Flashcards

6 cards from real CPT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 6 CPT Emissions & Environmental Standards flashcards as text

  1. Under US EPA regulations, what is the primary purpose of the On-Board Diagnostics II (OBD-II) system in relation to emissions?

    Answer: To continuously monitor emission-related components and alert the driver via the MIL when thresholds are exceeded

    OBD-II continuously monitors emission-related systems and illuminates the MIL when a fault could cause emissions to exceed 1.5 times the applicable standard.

  2. Which exhaust gas component is the primary indicator of catalytic converter efficiency during an emissions test?

    Answer: Hydrocarbons (HC)

    Hydrocarbons indicate unburned fuel passing through the catalyst; a functioning converter oxidizes HCs to CO2 and H2O, so high HC levels indicate converter failure.

  3. A vehicle fails an I/M 240 emissions test with high NOx readings. Which engine operating condition is MOST responsible for elevated NOx production?

    Answer: Excessively lean air-fuel mixture combined with high combustion temperatures

    NOx forms when nitrogen and oxygen react at very high temperatures — lean mixtures burn hotter and promote NOx formation.

  4. What is the three-way catalytic converter (TWC) designed to simultaneously reduce?

    Answer: Hydrocarbons (HC), Carbon Monoxide (CO), and Nitrogen Oxides (NOx)

    A three-way catalyst oxidizes HC and CO while simultaneously reducing NOx, requiring near-stoichiometric operation to function efficiently.

  5. Under California CARB regulations, what is the significance of a vehicle being classified as a PZEV (Partial Zero Emission Vehicle)?

    Answer: It meets near-zero tailpipe emissions standards and has zero evaporative emissions with a 15-year/150,000-mile emission warranty

    PZEV certification requires extremely low tailpipe emissions, zero evaporative emissions, and an extended 15-year/150,000-mile warranty on emission components.

  6. A CPT technician working on a fleet vehicle must ensure compliance with EPA Tier 3 emission standards. Compared to Tier 2, what is the most significant change in Tier 3 requirements?

    Answer: Significantly lower particulate matter and combined NOx+NMOG standards, and lower sulfur content in gasoline

    EPA Tier 3 aligns vehicle standards with California LEV III and significantly tightens PM and combined NOx+NMOG limits while requiring 10 ppm sulfur gasoline.