Practice Test GeeksCEI - Certified Emission Inspector Practice Test
← All CEI Flashcard Decks

Evaporative Emission Control Systems Flashcards

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

Read the first 7 Evaporative Emission Control Systems flashcards as text

  1. During a smoke machine test of an EVAP system, where is the smoke typically introduced?

    Answer: Into the EVAP service port or vent solenoid port

    Smoke is introduced into the EVAP system through the service port or vent solenoid port with the purge valve closed, allowing the technician to pressurize the sealed system and visually locate any leaks.

  2. What is the function of the canister vent valve (vent solenoid) in an EVAP system?

    Answer: It opens to allow fresh air into the canister during purge and closes during leak tests

    The canister vent valve allows fresh air into the canister during purge operations (so vapors are swept into the engine) and closes during PCM-commanded EVAP leak tests to seal the system.

  3. A P0446 diagnostic trouble code is most associated with which EVAP system component?

    Answer: Canister vent control valve circuit

    P0446 is defined as 'Evaporative Emission Control System Vent Control Circuit Malfunction,' indicating an electrical or functional fault in the canister vent valve circuit.

  4. What constitutes a 'gross leak' in OBD II EVAP system terminology?

    Answer: A leak equal to or larger than approximately 0.080-inch orifice equivalent

    A gross leak in OBD II terms is typically equivalent to an orifice of 0.080 inches or larger; a missing or loose fuel cap is a common cause and triggers a P0455 code.

  5. Which of the following BEST describes a non-intrusive OBD II EVAP test?

    Answer: The PCM commands tests using natural driving conditions without external equipment

    Non-intrusive EVAP tests use the vehicle's own PCM and existing components—such as the FTP sensor, purge valve, and vent valve—to conduct leak checks without any shop equipment connected to the vehicle.

  6. What effect does a saturated (fuel-soaked) charcoal canister have on vehicle emissions?

    Answer: It causes excessive hydrocarbon emissions and can damage the purge valve or engine

    A saturated canister can allow liquid fuel to reach and damage the purge solenoid, flood the engine, and allow fuel vapors to escape to the atmosphere, significantly increasing hydrocarbon emissions.

  7. Which driving cycle condition is most likely to allow an EVAP large leak monitor to complete?

    Answer: Cold start followed by a warm-up period with moderate city driving

    Many EVAP monitors require a cold start (engine at ambient temperature after extended soak) followed by warm-up, since the PCM uses natural fuel tank pressure/vacuum changes during heat soak to detect leaks.