SMOG INSPECTOR STUDY GUIDE BAR EXAM – QUESTIONS AND ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains
1. Bureau of Automotive Repair (BAR) Regulations and Program Administration
2. Visual Inspection Procedures for Emission Control Systems
3. Functional Tests: OBD I, OBD II, and BAR-97 (ASM and TSI)
4. On-Board Diagnostics (OBD II) System Operation and Monitor Readiness
5. Exhaust Gas Analysis and Pass/Fail Criteria
6. Fuel Evaporative (EVAP) System Testing and Diagnosis
7. Diesel Emissions Inspection Procedures (Clean Truck Check)
8. Inspector Safety, Ethics, and Consumer Protection Laws
Introduction
This comprehensive assessment is designed to prepare candidates for the Smog Check Inspector licensing examination
administered by the California Bureau of Automotive Repair. The exam evaluates a candidate's fundamental knowledge
of engine and emission control systems, mastery of state-specific inspection procedures, and the ability to apply critical
thinking to real-world scenarios. Success requires not only memorization of regulations but also the practical
application of diagnostic skills, understanding of OBD II systems, and strict adherence to safety and ethical guidelines.
The following questions cover visual inspections, functional testing, and compliance requirements to ensure a well-
rounded preparation for professional certification.
,Question 1
During a visual inspection, the inspector notices the oxygen (O2) sensor wire has been extended with a spliced
connection. What is the correct procedure?
A. Pass the inspection if the connection is soldered and insulated
B. Mark the vehicle as a "Gross Polluter"
C. Mark as "Tampered" for the O2 sensor in the inspection system
D. Refer the vehicle to a STAR station for further evaluation
🟢 Correct Answer: C. Mark as "Tampered" for the O2 sensor in the inspection system
🔴 Explanation: Emission-related components must be present, correctly connected, and free from unauthorized
modifications. An extended wire is considered a modification that interferes with the integrity of the emission
control system . The correct procedure is to enter "tamper" for the O2 sensor in the inspection system.
Question 2
What is the primary cause of photochemical smog formation?
A. Carbon dioxide and water vapor in the presence of sunlight
B. Hydrocarbons (HC) and Nitrogen Oxides (NOx) in the presence of sunlight
C. Carbon monoxide and particulate matter from diesel engines
D. Sulfur dioxide and nitrogen dioxide from industrial sources
🟢 Correct Answer: B. Hydrocarbons (HC) and Nitrogen Oxides (NOx) in the presence of sunlight
🔴 Explanation: Photochemical smog is caused by the reaction of hydrocarbons (HC) and nitrogen oxides (NOx) in
the presence of sunlight. This reaction produces secondary pollutants like ozone and other harmful compounds .
Question 3
A 2007 Class A Motor Home is presented for inspection with a gasoline V10 engine from a 2004 model year. Which
of the following steps should the inspector take?
A. Proceed with the inspection as the engine is from the same manufacturer
B. Check for a BAR Referee Label or verify the engine change is approved
,C. Automatically fail the vehicle for an engine change
D. Perform the inspection using the 2004 model year emissions standards
🟢 Correct Answer: B. Check for a BAR Referee Label or verify the engine change is approved
🔴 Explanation: When a vehicle has an engine change, the inspector must verify that the engine change is
compliant. This typically requires a BAR Referee label indicating the new engine configuration has been inspected
and approved. Vehicles with engine changes offered for that same year and model by the manufacturer do not
require a BAR Referee Label .
Question 4
During a BAR-97 pretest procedure, the "HC hang-up in progress" message takes an excessive amount of time while
the probe is on its hanger. Which of the following actions should the Inspector take?
A. Immediately replace the sample hose
B. Turn on "Zero air" to clear the analyzer
C. Abort the test and contact technical support
D. Bypass the hang-up procedure and continue the test
🟢 Correct Answer: B. Turn on "Zero air" to clear the analyzer
🔴 Explanation: During a BAR-97 pretest, if the HC hang-up procedure is taking excessive time, the inspector should
turn on "Zero air." This action helps to clear the analyzer and purge residual hydrocarbons from the system .
Question 5
What is the maximum allowable drive axle weight for a vehicle to be tested on a dynamometer during a Smog
Check?
A. 7,500 lbs
B. 5,000 lbs
C. 8,500 lbs
D. 6,000 lbs
🟢 Correct Answer: B. 5,000 lbs
, 🔴 Explanation: The maximum allowable drive axle weight for dynamometer testing is 5,000 lbs . Vehicles exceeding
this weight may be subject to different testing procedures or exemptions.
Question 6
A Smog Check Inspector smells fuel during an under-hood inspection but finds no visible signs of a leak. What
should the inspector do next?
A. Pass the vehicle as no leak is visible
B. Stop the inspection and investigate the source of the smell
C. Proceed with the test as the smell will dissipate
D. Note the smell as a comment but continue the inspection
🟢 Correct Answer: B. Stop the inspection and investigate the source of the smell
🔴 Explanation: A fuel smell indicates a potential safety hazard and a possible emissions system failure. The
inspector should not continue blindly; they must stop the inspection and investigate to identify the source of the
fuel smell .
Question 7
Which of the following is a correct test sequence for a Two-Speed Idle (TSI) test?
A. 2500 RPM and 1500 RPM
B. 2000 RPM and idle
C. 2500 RPM and idle
D. 3000 RPM and 1500 RPM
🟢 Correct Answer: C. 2500 RPM and idle
🔴 Explanation: The Two-Speed Idle (TSI) test consists of two test sequences: a high-speed test at 2500 RPM (which
must be maintained for 15 seconds) and a low-speed test at idle . This test is typically used for vehicles that cannot
be tested on a dynamometer.
Question 8
A customer brings in a vehicle for a smog check. The vehicle requires an ASM test but has traction control. The
ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
Core Domains
1. Bureau of Automotive Repair (BAR) Regulations and Program Administration
2. Visual Inspection Procedures for Emission Control Systems
3. Functional Tests: OBD I, OBD II, and BAR-97 (ASM and TSI)
4. On-Board Diagnostics (OBD II) System Operation and Monitor Readiness
5. Exhaust Gas Analysis and Pass/Fail Criteria
6. Fuel Evaporative (EVAP) System Testing and Diagnosis
7. Diesel Emissions Inspection Procedures (Clean Truck Check)
8. Inspector Safety, Ethics, and Consumer Protection Laws
Introduction
This comprehensive assessment is designed to prepare candidates for the Smog Check Inspector licensing examination
administered by the California Bureau of Automotive Repair. The exam evaluates a candidate's fundamental knowledge
of engine and emission control systems, mastery of state-specific inspection procedures, and the ability to apply critical
thinking to real-world scenarios. Success requires not only memorization of regulations but also the practical
application of diagnostic skills, understanding of OBD II systems, and strict adherence to safety and ethical guidelines.
The following questions cover visual inspections, functional testing, and compliance requirements to ensure a well-
rounded preparation for professional certification.
,Question 1
During a visual inspection, the inspector notices the oxygen (O2) sensor wire has been extended with a spliced
connection. What is the correct procedure?
A. Pass the inspection if the connection is soldered and insulated
B. Mark the vehicle as a "Gross Polluter"
C. Mark as "Tampered" for the O2 sensor in the inspection system
D. Refer the vehicle to a STAR station for further evaluation
🟢 Correct Answer: C. Mark as "Tampered" for the O2 sensor in the inspection system
🔴 Explanation: Emission-related components must be present, correctly connected, and free from unauthorized
modifications. An extended wire is considered a modification that interferes with the integrity of the emission
control system . The correct procedure is to enter "tamper" for the O2 sensor in the inspection system.
Question 2
What is the primary cause of photochemical smog formation?
A. Carbon dioxide and water vapor in the presence of sunlight
B. Hydrocarbons (HC) and Nitrogen Oxides (NOx) in the presence of sunlight
C. Carbon monoxide and particulate matter from diesel engines
D. Sulfur dioxide and nitrogen dioxide from industrial sources
🟢 Correct Answer: B. Hydrocarbons (HC) and Nitrogen Oxides (NOx) in the presence of sunlight
🔴 Explanation: Photochemical smog is caused by the reaction of hydrocarbons (HC) and nitrogen oxides (NOx) in
the presence of sunlight. This reaction produces secondary pollutants like ozone and other harmful compounds .
Question 3
A 2007 Class A Motor Home is presented for inspection with a gasoline V10 engine from a 2004 model year. Which
of the following steps should the inspector take?
A. Proceed with the inspection as the engine is from the same manufacturer
B. Check for a BAR Referee Label or verify the engine change is approved
,C. Automatically fail the vehicle for an engine change
D. Perform the inspection using the 2004 model year emissions standards
🟢 Correct Answer: B. Check for a BAR Referee Label or verify the engine change is approved
🔴 Explanation: When a vehicle has an engine change, the inspector must verify that the engine change is
compliant. This typically requires a BAR Referee label indicating the new engine configuration has been inspected
and approved. Vehicles with engine changes offered for that same year and model by the manufacturer do not
require a BAR Referee Label .
Question 4
During a BAR-97 pretest procedure, the "HC hang-up in progress" message takes an excessive amount of time while
the probe is on its hanger. Which of the following actions should the Inspector take?
A. Immediately replace the sample hose
B. Turn on "Zero air" to clear the analyzer
C. Abort the test and contact technical support
D. Bypass the hang-up procedure and continue the test
🟢 Correct Answer: B. Turn on "Zero air" to clear the analyzer
🔴 Explanation: During a BAR-97 pretest, if the HC hang-up procedure is taking excessive time, the inspector should
turn on "Zero air." This action helps to clear the analyzer and purge residual hydrocarbons from the system .
Question 5
What is the maximum allowable drive axle weight for a vehicle to be tested on a dynamometer during a Smog
Check?
A. 7,500 lbs
B. 5,000 lbs
C. 8,500 lbs
D. 6,000 lbs
🟢 Correct Answer: B. 5,000 lbs
, 🔴 Explanation: The maximum allowable drive axle weight for dynamometer testing is 5,000 lbs . Vehicles exceeding
this weight may be subject to different testing procedures or exemptions.
Question 6
A Smog Check Inspector smells fuel during an under-hood inspection but finds no visible signs of a leak. What
should the inspector do next?
A. Pass the vehicle as no leak is visible
B. Stop the inspection and investigate the source of the smell
C. Proceed with the test as the smell will dissipate
D. Note the smell as a comment but continue the inspection
🟢 Correct Answer: B. Stop the inspection and investigate the source of the smell
🔴 Explanation: A fuel smell indicates a potential safety hazard and a possible emissions system failure. The
inspector should not continue blindly; they must stop the inspection and investigate to identify the source of the
fuel smell .
Question 7
Which of the following is a correct test sequence for a Two-Speed Idle (TSI) test?
A. 2500 RPM and 1500 RPM
B. 2000 RPM and idle
C. 2500 RPM and idle
D. 3000 RPM and 1500 RPM
🟢 Correct Answer: C. 2500 RPM and idle
🔴 Explanation: The Two-Speed Idle (TSI) test consists of two test sequences: a high-speed test at 2500 RPM (which
must be maintained for 15 seconds) and a low-speed test at idle . This test is typically used for vehicles that cannot
be tested on a dynamometer.
Question 8
A customer brings in a vehicle for a smog check. The vehicle requires an ASM test but has traction control. The
