California Smog Check Inspector Exam
QUESTIONS WITH CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A PDF
1. During a Smog Check inspection, a vehicle’s malfunction indicator lamp (MIL)
does not illuminate during key-on engine-off testing. The inspector should:
A. Continue inspection normally
B. Fail the vehicle for MIL malfunction
C. Disconnect the battery
D. Pass the vehicle if no codes are stored
Answer: B
Rationale: The MIL must illuminate during KOEO testing to verify bulb and system
function.
2. A vehicle arrives for inspection with visible black smoke from the exhaust
during acceleration. This MOST likely indicates:
A. Lean fuel mixture
B. Excessive fuel delivery or incomplete combustion
C. Proper combustion efficiency
D. Evaporative emission failure only
Answer: B
Rationale: Black smoke indicates rich fuel conditions or poor combustion.
3. Before beginning a Smog Check inspection, the inspector should FIRST:
,A. Disconnect the battery
B. Verify vehicle identity and required documentation
C. Remove emissions labels
D. Clear stored diagnostic trouble codes
Answer: B
Rationale: Vehicle identification verification is required before testing.
4. A vehicle’s OBD-II system reports catalyst monitor “not ready.” The inspector
should:
A. Automatically pass the vehicle
B. Follow California readiness monitor rules
C. Disconnect the scan tool
D. Ignore monitor status
Answer: B
Rationale: California regulations specify allowable incomplete monitors.
5. A Smog Check inspector notices a disconnected vacuum hose under the hood.
This condition should result in:
A. Immediate pass
B. Visual inspection failure
C. Ignoring the condition if emissions are low
D. Battery reset only
Answer: B
Rationale: Tampered or disconnected emissions components fail visual inspection.
6. A gasoline vehicle emits high hydrocarbon (HC) levels at idle. The MOST likely
cause is:
A. Misfire or incomplete combustion
B. Excess oxygen in exhaust
,C. Proper fuel atomization
D. Efficient catalytic converter function
Answer: A
Rationale: Misfires cause unburned fuel and elevated HC emissions.
7. A Smog Check inspector must reject a vehicle from testing if:
A. Tires are dirty
B. Vehicle cannot be safely tested
C. Fuel tank is full
D. Air conditioning is operational
Answer: B
Rationale: Unsafe testing conditions require rejection.
8. During inspection, the catalytic converter appears recently installed but lacks
required labeling. The inspector should:
A. Pass the component automatically
B. Fail the vehicle for improper catalytic converter
C. Ignore label requirements
D. Disconnect the OBD-II system
Answer: B
Rationale: California requires approved and labeled catalytic converters.
9. A vehicle’s check engine light is commanded ON with stored emissions-
related trouble codes. The vehicle should:
A. Pass automatically
B. Fail the inspection
C. Be exempt from testing
D. Have codes cleared immediately
, Answer: B
Rationale: Active emissions faults cause inspection failure.
10. The PRIMARY purpose of the evaporative emissions system is to:
A. Reduce coolant temperature
B. Prevent fuel vapor release into atmosphere
C. Increase engine compression
D. Improve tire pressure
Answer: B
Rationale: EVAP systems control fuel vapor emissions.
11. A vehicle fails the functional gas cap test. The MOST likely issue is:
A. Damaged or leaking gas cap seal
B. Faulty catalytic converter
C. Low coolant level
D. Proper EVAP operation
Answer: A
Rationale: Leaking caps allow fuel vapor escape.
12. During a visual inspection, an EGR valve is missing. The inspector should:
A. Continue testing normally
B. Fail the vehicle for tampering
C. Ignore missing component
D. Disconnect battery before test
Answer: B
Rationale: Missing emissions equipment is tampering.
13. A vehicle’s oxygen sensor is malfunctioning. This MOST likely causes:
QUESTIONS WITH CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A PDF
1. During a Smog Check inspection, a vehicle’s malfunction indicator lamp (MIL)
does not illuminate during key-on engine-off testing. The inspector should:
A. Continue inspection normally
B. Fail the vehicle for MIL malfunction
C. Disconnect the battery
D. Pass the vehicle if no codes are stored
Answer: B
Rationale: The MIL must illuminate during KOEO testing to verify bulb and system
function.
2. A vehicle arrives for inspection with visible black smoke from the exhaust
during acceleration. This MOST likely indicates:
A. Lean fuel mixture
B. Excessive fuel delivery or incomplete combustion
C. Proper combustion efficiency
D. Evaporative emission failure only
Answer: B
Rationale: Black smoke indicates rich fuel conditions or poor combustion.
3. Before beginning a Smog Check inspection, the inspector should FIRST:
,A. Disconnect the battery
B. Verify vehicle identity and required documentation
C. Remove emissions labels
D. Clear stored diagnostic trouble codes
Answer: B
Rationale: Vehicle identification verification is required before testing.
4. A vehicle’s OBD-II system reports catalyst monitor “not ready.” The inspector
should:
A. Automatically pass the vehicle
B. Follow California readiness monitor rules
C. Disconnect the scan tool
D. Ignore monitor status
Answer: B
Rationale: California regulations specify allowable incomplete monitors.
5. A Smog Check inspector notices a disconnected vacuum hose under the hood.
This condition should result in:
A. Immediate pass
B. Visual inspection failure
C. Ignoring the condition if emissions are low
D. Battery reset only
Answer: B
Rationale: Tampered or disconnected emissions components fail visual inspection.
6. A gasoline vehicle emits high hydrocarbon (HC) levels at idle. The MOST likely
cause is:
A. Misfire or incomplete combustion
B. Excess oxygen in exhaust
,C. Proper fuel atomization
D. Efficient catalytic converter function
Answer: A
Rationale: Misfires cause unburned fuel and elevated HC emissions.
7. A Smog Check inspector must reject a vehicle from testing if:
A. Tires are dirty
B. Vehicle cannot be safely tested
C. Fuel tank is full
D. Air conditioning is operational
Answer: B
Rationale: Unsafe testing conditions require rejection.
8. During inspection, the catalytic converter appears recently installed but lacks
required labeling. The inspector should:
A. Pass the component automatically
B. Fail the vehicle for improper catalytic converter
C. Ignore label requirements
D. Disconnect the OBD-II system
Answer: B
Rationale: California requires approved and labeled catalytic converters.
9. A vehicle’s check engine light is commanded ON with stored emissions-
related trouble codes. The vehicle should:
A. Pass automatically
B. Fail the inspection
C. Be exempt from testing
D. Have codes cleared immediately
, Answer: B
Rationale: Active emissions faults cause inspection failure.
10. The PRIMARY purpose of the evaporative emissions system is to:
A. Reduce coolant temperature
B. Prevent fuel vapor release into atmosphere
C. Increase engine compression
D. Improve tire pressure
Answer: B
Rationale: EVAP systems control fuel vapor emissions.
11. A vehicle fails the functional gas cap test. The MOST likely issue is:
A. Damaged or leaking gas cap seal
B. Faulty catalytic converter
C. Low coolant level
D. Proper EVAP operation
Answer: A
Rationale: Leaking caps allow fuel vapor escape.
12. During a visual inspection, an EGR valve is missing. The inspector should:
A. Continue testing normally
B. Fail the vehicle for tampering
C. Ignore missing component
D. Disconnect battery before test
Answer: B
Rationale: Missing emissions equipment is tampering.
13. A vehicle’s oxygen sensor is malfunctioning. This MOST likely causes:
