1
SMOG Level 1 Practice Test Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified –
Pass Guaranteed – A+ Graded
Q1: During a pre-inspection vehicle check, you notice a leaking fuel injector dripping gasoline
onto the exhaust manifold. What is the correct action according to safety protocols?
A. Proceed with the inspection but note the leak on the VIR.
B. Ask the customer to move the vehicle away from the bay immediately.
C. Clean the area with a rag and begin the OBDII check.
D. Refuse to inspect the vehicle due to the safety hazard. [CORRECT]
Correct Answer: D
Rationale: Correct because a fuel leak onto a hot exhaust manifold presents an immediate fire
hazard; regulations require the inspection to be refused if a safety defect exists that endangers the
technician or equipment.
Q2: A 1998 gasoline-powered vehicle arrives for a Smog Check. Which of the following
emission control systems must be visually inspected and confirmed to be present and connected?
A. On-Board Refueling Vapor Recovery (ORVR).
B. Positive Crankcase Ventilation (PCV). [CORRECT]
**C. Evaporative System Monitor (non-continuous).
D. Exhaust Gas Recirculation (EGR) Valve (if equipped).
Correct Answer: B
Rationale: Correct because the PCV system is a required visual inspection item for all 1976 and
older gasoline-powered vehicles, whereas the EGR is only required if the vehicle was originally
equipped with it.
,2
Q3: When performing an OBDII test, the "Check Engine" light does not illuminate during the
bulb check phase of the key on/engine off (KOEO) procedure. What is the next step?
A. Clear the codes and attempt to re-communicate.
B. Proceed with the inspection as the light may work while driving.
C. Fail the vehicle for a malfunctioning MIL. [CORRECT]
D. Consult the vehicle's service manual for fuse locations.
Correct Answer: C
Rationale: Correct because a functional Malfunction Indicator Light (MIL) is mandatory for the
OBDII inspection; if it does not illuminate during the self-test, the vehicle fails the functional
check.
Q4: What is the maximum diameter of a hole allowed in the exhaust system before the catalytic
converter for a vehicle subject to a visual inspection?
A. 1/2 inch.
B. 1 inch.
C. No holes are allowed. [CORRECT]
D. 2 inches.
Correct Answer: C
Rationale: Correct because the exhaust system must be free of leaks or defects upstream of the
catalyst; any hole, regardless of size, constitutes a failure for the visual inspection.
Q5: Which of the following vehicles is exempt from the biennial Smog Check requirement in
California (assuming standard registration)?
A. A 2022 gasoline-powered sedan.
B. A 1975 gasoline-powered pickup truck.
C. An electric vehicle (EV). [CORRECT]
D. A diesel-powered motorhome.
,3
Correct Answer: C
Rationale: Correct because electric vehicles produce zero tailpipe emissions and are completely
exempt from smog inspection requirements; gasoline vehicles 8 model years and newer are
subject to an abatement fee rather than a test, and 1975 and older gas vehicles are exempt but
diesels 1998 and newer are not.
Q6: A vehicle fails the smog inspection for high CO (Carbon Monoxide). Which system is most
likely the cause of this failure?
A. Exhaust Gas Recirculation (EGR).
B. Fuel delivery system. [CORRECT]
C. Ignition timing (advanced).
D. Catalytic converter efficiency.
Correct Answer: B
Rationale: Correct because high CO is typically caused by a rich fuel condition where there is
not enough air to burn the fuel completely, implicating the fuel delivery system (injectors,
pressure regulator) or air intake.
Q7: You are inspecting a vehicle with a BAR-OBD interface card. The vehicle is a 2000 model
year. The OBDII scan tool retrieves Diagnostic Trouble Codes (DTCs). Which of the following
codes indicates a catalyst efficiency failure?
A. P0300.
B. P0440.
C. P0420. [CORRECT]
D. P0171.
Correct Answer: C
Rationale: Correct because DTC P0420 is the universal OBDII code for "Catalyst System
Efficiency Below Threshold (Bank 1)," directly indicating a catalytic converter failure.
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Q8: When performing the Two-Speed Idle (TSI) test, what are the two specified RPM ranges at
which emissions are measured?
A. 1000-1100 RPM and 2000-2100 RPM.
B. 1200-1300 RPM and 2500-2600 RPM.
C. 2500 ± 100 RPM (High) and 1000-1200 RPM (Low/Cruise). [CORRECT]
D. 1500 RPM and 3000 RPM.
Correct Answer: C
Rationale: Correct because the BAR TSI procedure requires emissions measurement at a high
speed of 2500 RPM (+/- 100 RPM) to simulate load, followed by a low idle or cruise speed
typically around 1000 to 1200 RPM.
Q9: During a visual inspection, you notice a "dummy" or aftermarket catalytic converter
installed on a 2005 vehicle, but there is no Executive Order (EO) number stamped on it. How do
you proceed?
A. Pass the device if it looks like a catalyst.
B. Fail the vehicle for a missing or unauthorized catalytic converter. [CORRECT]
**C. Ask the customer for the receipt.
D. Install a new EO-numbered converter yourself.
Correct Answer: B
Rationale: Correct because aftermarket catalytic converters must have a valid CARB Executive
Order number stamped on the shell to be legal in California; absence of this number is an
automatic failure.
Q10: What is the primary function of the Evaporative (EVAP) system?
A. To burn excess fuel in the exhaust manifold.
B. To prevent fuel vapors from escaping into the atmosphere. [CORRECT]
SMOG Level 1 Practice Test Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified –
Pass Guaranteed – A+ Graded
Q1: During a pre-inspection vehicle check, you notice a leaking fuel injector dripping gasoline
onto the exhaust manifold. What is the correct action according to safety protocols?
A. Proceed with the inspection but note the leak on the VIR.
B. Ask the customer to move the vehicle away from the bay immediately.
C. Clean the area with a rag and begin the OBDII check.
D. Refuse to inspect the vehicle due to the safety hazard. [CORRECT]
Correct Answer: D
Rationale: Correct because a fuel leak onto a hot exhaust manifold presents an immediate fire
hazard; regulations require the inspection to be refused if a safety defect exists that endangers the
technician or equipment.
Q2: A 1998 gasoline-powered vehicle arrives for a Smog Check. Which of the following
emission control systems must be visually inspected and confirmed to be present and connected?
A. On-Board Refueling Vapor Recovery (ORVR).
B. Positive Crankcase Ventilation (PCV). [CORRECT]
**C. Evaporative System Monitor (non-continuous).
D. Exhaust Gas Recirculation (EGR) Valve (if equipped).
Correct Answer: B
Rationale: Correct because the PCV system is a required visual inspection item for all 1976 and
older gasoline-powered vehicles, whereas the EGR is only required if the vehicle was originally
equipped with it.
,2
Q3: When performing an OBDII test, the "Check Engine" light does not illuminate during the
bulb check phase of the key on/engine off (KOEO) procedure. What is the next step?
A. Clear the codes and attempt to re-communicate.
B. Proceed with the inspection as the light may work while driving.
C. Fail the vehicle for a malfunctioning MIL. [CORRECT]
D. Consult the vehicle's service manual for fuse locations.
Correct Answer: C
Rationale: Correct because a functional Malfunction Indicator Light (MIL) is mandatory for the
OBDII inspection; if it does not illuminate during the self-test, the vehicle fails the functional
check.
Q4: What is the maximum diameter of a hole allowed in the exhaust system before the catalytic
converter for a vehicle subject to a visual inspection?
A. 1/2 inch.
B. 1 inch.
C. No holes are allowed. [CORRECT]
D. 2 inches.
Correct Answer: C
Rationale: Correct because the exhaust system must be free of leaks or defects upstream of the
catalyst; any hole, regardless of size, constitutes a failure for the visual inspection.
Q5: Which of the following vehicles is exempt from the biennial Smog Check requirement in
California (assuming standard registration)?
A. A 2022 gasoline-powered sedan.
B. A 1975 gasoline-powered pickup truck.
C. An electric vehicle (EV). [CORRECT]
D. A diesel-powered motorhome.
,3
Correct Answer: C
Rationale: Correct because electric vehicles produce zero tailpipe emissions and are completely
exempt from smog inspection requirements; gasoline vehicles 8 model years and newer are
subject to an abatement fee rather than a test, and 1975 and older gas vehicles are exempt but
diesels 1998 and newer are not.
Q6: A vehicle fails the smog inspection for high CO (Carbon Monoxide). Which system is most
likely the cause of this failure?
A. Exhaust Gas Recirculation (EGR).
B. Fuel delivery system. [CORRECT]
C. Ignition timing (advanced).
D. Catalytic converter efficiency.
Correct Answer: B
Rationale: Correct because high CO is typically caused by a rich fuel condition where there is
not enough air to burn the fuel completely, implicating the fuel delivery system (injectors,
pressure regulator) or air intake.
Q7: You are inspecting a vehicle with a BAR-OBD interface card. The vehicle is a 2000 model
year. The OBDII scan tool retrieves Diagnostic Trouble Codes (DTCs). Which of the following
codes indicates a catalyst efficiency failure?
A. P0300.
B. P0440.
C. P0420. [CORRECT]
D. P0171.
Correct Answer: C
Rationale: Correct because DTC P0420 is the universal OBDII code for "Catalyst System
Efficiency Below Threshold (Bank 1)," directly indicating a catalytic converter failure.
, 4
Q8: When performing the Two-Speed Idle (TSI) test, what are the two specified RPM ranges at
which emissions are measured?
A. 1000-1100 RPM and 2000-2100 RPM.
B. 1200-1300 RPM and 2500-2600 RPM.
C. 2500 ± 100 RPM (High) and 1000-1200 RPM (Low/Cruise). [CORRECT]
D. 1500 RPM and 3000 RPM.
Correct Answer: C
Rationale: Correct because the BAR TSI procedure requires emissions measurement at a high
speed of 2500 RPM (+/- 100 RPM) to simulate load, followed by a low idle or cruise speed
typically around 1000 to 1200 RPM.
Q9: During a visual inspection, you notice a "dummy" or aftermarket catalytic converter
installed on a 2005 vehicle, but there is no Executive Order (EO) number stamped on it. How do
you proceed?
A. Pass the device if it looks like a catalyst.
B. Fail the vehicle for a missing or unauthorized catalytic converter. [CORRECT]
**C. Ask the customer for the receipt.
D. Install a new EO-numbered converter yourself.
Correct Answer: B
Rationale: Correct because aftermarket catalytic converters must have a valid CARB Executive
Order number stamped on the shell to be legal in California; absence of this number is an
automatic failure.
Q10: What is the primary function of the Evaporative (EVAP) system?
A. To burn excess fuel in the exhaust manifold.
B. To prevent fuel vapors from escaping into the atmosphere. [CORRECT]
