Smog Check Technician Certification Exam — Questions and Answers

Question 1: A transfer from a leasing company to the vehicle's lessee is:

Exempt from change-of-ownership Smog Check when the lessee was the operator (Correct answer)
Exempt only for diesel vehicles
Subject to a Test-Only inspection
Always subject to a Referee inspection

Correct answer: Exempt from change-of-ownership Smog Check when the lessee was the operator

Lessor-to-lessee transfers where the lessee is the current operator are exempt.

Question 2: Which component is inspected for visible damage or tampering?

Dashboard
Catalytic converter (Correct answer)
Air filter
Oil pan

Correct answer: Catalytic converter

The catalytic converter is a crucial component of a vehicle's emissions control system, designed to reduce harmful pollutants in the exhaust. During a smog check, inspectors specifically look for visible damage, signs of tampering, or illegal modifications to this part. Any issues with the catalytic converter can severely compromise the vehicle's ability to meet emissions standards.

Question 3: How many consecutive confirmed detections (drive cycles) does an OBD II system typically require before setting a confirmed DTC and illuminating the MIL?

Ten drive cycles
One drive cycle
Two consecutive drive cycles (Correct answer)
Five drive cycles

Correct answer: Two consecutive drive cycles

Most OBD II monitors require a fault to be detected in two consecutive drive cycles before setting a confirmed DTC and illuminating the MIL, helping prevent false positives from transient conditions.

Question 4: What is the Malfunction Indicator Lamp (MIL) commonly known as to most vehicle owners?

Temperature warning light
Check Engine light (Correct answer)
Oil pressure warning light
Battery warning light

Correct answer: Check Engine light

The MIL is commonly known as the 'Check Engine' light (some manufacturers label it 'Service Engine Soon'), and its illumination indicates the OBD II system has detected an emission-related fault.

Question 5: Which item does the OIS barcode scanner typically read to reduce data-entry errors?

The oil filter part number
The tire sidewall
The license plate frame
The vehicle's VIN barcode or the DMV renewal notice (Correct answer)

Correct answer: The vehicle's VIN barcode or the DMV renewal notice

Scanning the VIN or DMV notice barcode avoids keying mistakes and improves data integrity.

Question 6: Who purchases Smog Check certificates of compliance from BAR?

Individual technicians
The vehicle owner online
Licensed Smog Check stations (Correct answer)
The DMV

Correct answer: Licensed Smog Check stations

Stations buy certificates from BAR, and certificates are issued electronically when a vehicle passes.

Question 7: How long must California automotive repair dealers, including Smog Check stations, generally keep invoices and inspection records?

90 days
5 years
At least 3 years (Correct answer)
1 year

Correct answer: At least 3 years

Under California's Automotive Repair Act, records must be kept for at least three years and made available to BAR.

Question 8: Using a known-clean vehicle's OBD data to certify a different vehicle is called:

Readiness resetting
Gross polluting
Dilution testing
Clean scanning (Correct answer)

Correct answer: Clean scanning

Clean scanning is fraudulent and results in license discipline and possible criminal charges.

Question 9: A gasoline-powered hybrid vehicle that is past its new-vehicle exemption period:

Only needs testing at change of ownership
Is subject to Smog Check (Correct answer)
Only needs a visual inspection
Is permanently exempt

Correct answer: Is subject to Smog Check

Hybrids have a combustion engine and are required to receive Smog Checks.

Question 10: A properly working upstream zirconia O2 sensor in closed loop should switch between approximately:

4 and 12 volts
1.5 and 2.5 volts
0 and 5 volts
0.1 and 0.9 volts (Correct answer)

Correct answer: 0.1 and 0.9 volts

A zirconia O2 sensor produces about 0.1 V when lean and about 0.9 V when rich as it switches around stoichiometry.

Question 11: What engine parameter does OBD II standard PID $05 (Mode 01, PID 05) report?

Throttle position percentage
Engine coolant temperature (Correct answer)
Vehicle speed
Engine RPM

Correct answer: Engine coolant temperature

OBD II PID $05 reports engine coolant temperature, which is critical for verifying the engine has reached normal operating temperature before accurate emission tests can be performed.

Question 12: A technician enters a valid license number but the wrong access code three times. What is the most likely result?

The system may lock out access until it is reset through BAR procedures (Correct answer)
The certificate prints automatically
The system bypasses the code
The test proceeds in demo mode

Correct answer: The system may lock out access until it is reset through BAR procedures

Repeated failed authentication attempts can lock access as a security control.

Question 13: An OBD inspection shows a calibration verification number (CVN) that does not match approved values for that vehicle. What does this suggest?

The fuel is of poor quality
The ECM software may have been modified (Correct answer)
The vehicle's tires are underinflated
The readiness monitors are complete

Correct answer: The ECM software may have been modified

A non-matching CVN indicates the ECM calibration may have been reprogrammed with unapproved software.

Question 14: Printed vehicle inspection reports that contain customer information are no longer needed and have passed their required retention period. How should they be disposed of?

Reuse the backs as scratch paper
Leave them in the customer waiting area
Shred them or use a secure document disposal service (Correct answer)
Put them in the regular recycling bin

Correct answer: Shred them or use a secure document disposal service

Secure destruction keeps personal information from being recovered from discarded records.

Question 15: A technician shares their BAR access credentials with a coworker who has no license. What is the main issue?

It violates BAR rules and lets unlicensed people perform inspections under the technician's name (Correct answer)
It is allowed if the coworker is supervised
It's only an issue at STAR stations
It's allowed during busy periods

Correct answer: It violates BAR rules and lets unlicensed people perform inspections under the technician's name

Inspections must be performed only by the licensed technician whose credentials are used, so sharing access is a serious violation.

Question 16: Which vehicle would most likely need a Referee rather than a regular station?

A vehicle with an engine swap that cannot be verified by normal reference data (Correct answer)
A 2015 sedan due for biennial check
A 2008 pickup at change of ownership
A 2003 minivan with a check engine light

Correct answer: A vehicle with an engine swap that cannot be verified by normal reference data

Referees handle engine changes, kit cars, gray market vehicles, and other cases requiring special determination.

Question 17: How long must test records typically be retained?

1 year
10 years
2 years (Correct answer)
6 months

Correct answer: 2 years

Regulatory bodies typically mandate that smog check stations retain all test records for a specific duration, commonly two years. This retention period is crucial for auditing purposes, allowing agencies to investigate complaints, verify compliance, and ensure transparency within the emissions testing program. It provides a historical record for accountability and program oversight.

Question 18: What does the EVAP system prevent?

Oil leaks
Fuel vapor emissions (Correct answer)
Coolant loss
Exhaust noise

Correct answer: Fuel vapor emissions

The EVAP (Evaporative Emission Control) system is designed to capture and store fuel vapors that evaporate from the fuel tank and fuel system components. Its primary purpose is to prevent these harmful hydrocarbon vapors from escaping into the atmosphere, which contributes to air pollution. By containing and eventually burning these vapors, the EVAP system plays a critical role in reducing environmental impact.

Question 19: Measuring 120 ohms across CAN High and CAN Low with the ignition off most likely means:

CAN High is shorted to CAN Low
The bus is perfectly normal
One terminating resistor or its circuit is open (Correct answer)
Both resistors are shorted

Correct answer: One terminating resistor or its circuit is open

Only one 120-ohm terminator is being measured, so the other is open.

Question 20: A fleet owner wants to perform Smog Checks on their own vehicles. This is possible if:

They have more than five vehicles
All vehicles are under eight years old
The fleet is licensed by BAR as a fleet station with licensed technicians (Correct answer)
They obtain DMV approval only

Correct answer: The fleet is licensed by BAR as a fleet station with licensed technicians

BAR licenses qualified fleets to test their own vehicles using licensed inspectors.

Question 21: Vehicles registered in certain rural ZIP codes outside enhanced and basic areas typically require a Smog Check:

Only at change of ownership or initial registration (Correct answer)
Every two years
Never under any circumstance
Every year

Correct answer: Only at change of ownership or initial registration

Change-of-ownership areas require smog certification only when the vehicle is transferred or initially registered.

Question 22: What is the main purpose of BAR's On-Board Inspection System (BAR-OIS) electronic data checks?

Scheduling customer appointments
Billing customers automatically
Verifying that the OBD data belongs to the tested vehicle and is accurate (Correct answer)
Recording tire tread depth

Correct answer: Verifying that the OBD data belongs to the tested vehicle and is accurate

BAR-OIS captures OBD data that helps detect fraud such as clean plugging and software tampering.

Question 23: A vehicle's gas cap fails the pressure decay test. What is the inspection result?

Fail the fuel cap functional test (Correct answer)
Skip the test and pass
Pass after tightening the cap during the test
Pass if the tailpipe readings are clean

Correct answer: Fail the fuel cap functional test

A cap that cannot hold pressure fails because it allows evaporative emissions to escape.

Question 24: A vehicle's OBD port communicates normally, but its supported-PID list matches a different manufacturer. What is the most appropriate action?

Issue the certificate anyway
Swap OBD cables until it passes
Use another vehicle's connection
Stop and confirm the right vehicle is connected; don't certify suspicious data (Correct answer)

Correct answer: Stop and confirm the right vehicle is connected; don't certify suspicious data

Data that doesn't match the vehicle is a clean-plugging warning sign and must never be certified.

Question 25: A coworker asks to borrow your Smog Check technician access code to finish an inspection while you are at lunch. What is the correct response?

Refuse, because each technician must use only their own credentials (Correct answer)
Write it down so they can log out afterward
Share it if the inspection is already in progress
Share it only if the station owner approves

Correct answer: Refuse, because each technician must use only their own credentials

Credentials tie each inspection record to one licensed technician, so sharing them is prohibited and can lead to license discipline.

Question 26: Which vehicles in California get an OBD-focused Smog Check instead of tailpipe testing?

Gasoline vehicles model year 2000 and newer (Correct answer)
All vehicles model year 1976 and newer
Only diesel vehicles before 1998
Only motorcycles

Correct answer: Gasoline vehicles model year 2000 and newer

Since 2015, model year 2000 and newer gasoline vehicles are inspected mainly with OBD through BAR-OIS.

Question 27: A technician's workstation shows a certificate or connection error when it tries to transmit test data to a remote server. What is the best first step?

Enter the results on a different computer under another technician's login
Turn off all security software permanently
Reinstall the operating system right away
Check the network connection and the system date and time, then follow the vendor's support procedures (Correct answer)

Correct answer: Check the network connection and the system date and time, then follow the vendor's support procedures

Connection and certificate errors are often caused by network problems or an incorrect system clock, and the vendor's procedures should be followed.

Question 28: Which vehicle is exempt from California's Smog Check requirement?

2010 diesel pickup under 14,000 lbs GVWR
1998 gasoline passenger car
2005 gasoline hybrid
1975 and older gasoline-powered vehicle (Correct answer)

Correct answer: 1975 and older gasoline-powered vehicle

Gasoline vehicles model year 1975 and older are exempt.

Question 29: During an OBD inspection, the OIS cannot establish communication with the vehicle. Which should the technician check first?

DLC power on pin 16 and grounds on pins 4 and 5 (Correct answer)
Catalytic converter efficiency
Evaporative purge valve operation
Fuel cap pressure test result

Correct answer: DLC power on pin 16 and grounds on pins 4 and 5

No power or ground at the DLC is the most common cause of a no-communication condition.

Question 30: Which emission gases does the analyzer measure during an ASM tailpipe test for pass/fail evaluation?

CO2, O2, and N2
HC, SO2, and particulate matter
Only CO
HC, CO, and NO (Correct answer)

Correct answer: HC, CO, and NO

Pass/fail limits for ASM are based on hydrocarbons, carbon monoxide, and nitric oxide.

Question 31: Which situation should a technician direct to a Smog Check Referee?

Any vehicle that fails a gas cap test
A vehicle needing an oil change
A vehicle with parts that cannot be verified as legal at a regular station (Correct answer)
Any vehicle older than 20 years

Correct answer: A vehicle with parts that cannot be verified as legal at a regular station

Referees handle special cases such as unverifiable configurations, engine changes, and disputed results.

Question 32: An OBD vehicle has a stored pending code but the MIL is off and monitors are ready. How does that pending code affect the Smog Check?

It does not cause a failure by itself, since only MIL-commanded codes fail (Correct answer)
It requires a tailpipe test instead
It designates the car as a gross polluter
It is an automatic failure

Correct answer: It does not cause a failure by itself, since only MIL-commanded codes fail

Failure is based on MIL-commanded DTCs; pending codes alone do not fail the vehicle.

Question 33: What is the recommended approach to staying current in Application Security & Development?

Relying solely on past experience
Reviewing initial training materials once per year
Waiting for regulatory changes to force updates
Regular professional development, industry publications, and peer collaboration (Correct answer)

Correct answer: Regular professional development, industry publications, and peer collaboration

Staying current in Application Security & Development requires ongoing professional development, reading industry publications, and collaborating with peers to share knowledge and best practices.

Question 34: Before beginning the tailpipe portion of a Smog Check on a 1990 vehicle, what engine condition must the technician ensure?

Engine is idling with the A/C on maximum
Engine has been off for at least 30 minutes
Engine is at normal operating temperature (Correct answer)
Engine is running at 2,500 rpm for 10 minutes with the hood closed

Correct answer: Engine is at normal operating temperature

Emissions readings are only valid when the engine and catalytic converter are at normal operating temperature.

Question 35: A technician suspects an inspection was performed fraudulently by a coworker. What is the most appropriate action?

Copy the method for difficult vehicles
Report the concern to BAR (Correct answer)
Ignore it to avoid conflict
Delete the test record

Correct answer: Report the concern to BAR

BAR investigates suspected Smog Check fraud, and reporting protects the program and honest licensees.

Question 36: The OIS reports a VIN mismatch between the VIN stored in the vehicle's ECU and the VIN entered for the test. What could this indicate?

A failed catalyst monitor
Possible clean scanning, where a different vehicle is plugged in (Correct answer)
Low fuel level
Normal sensor drift

Correct answer: Possible clean scanning, where a different vehicle is plugged in

A VIN mismatch can mean the OBD data came from a different vehicle, which is a known fraud pattern called clean scanning.

Question 37: Where are Smog Check test results transmitted after an inspection?

To the BAR Vehicle Information Database (VID) (Correct answer)
Directly to the vehicle manufacturer
To the EPA regional office
Only to the station's paper file

Correct answer: To the BAR Vehicle Information Database (VID)

The inspection system electronically sends results to BAR's VID, which also notifies DMV of certifications.

Question 38: 'Elasticity' in cloud computing refers to the ability to:

Stretch network cables over longer distances
Store data permanently without backups
Automatically scale resources up or down as demand changes (Correct answer)
Run software without any operating system

Correct answer: Automatically scale resources up or down as demand changes

Elastic systems add or remove capacity to match the current workload.

Question 39: What is 'clean plugging'?

Plugging vacuum leaks before testing
Connecting the OBD cable to a different, passing vehicle to obtain a fraudulent pass (Correct answer)
Resetting the inspection system after a power failure
Cleaning spark plugs before a test

Correct answer: Connecting the OBD cable to a different, passing vehicle to obtain a fraudulent pass

Clean plugging uses another vehicle's OBD data to falsely pass a vehicle, which is inspection fraud.

Question 40: Beginning with which model year were all new light-duty vehicles sold in the US required to use CAN for OBD-II communication?

2000
1996
2012
2008 (Correct answer)

Correct answer: 2008

Federal rules mandated ISO 15765 CAN diagnostics for all 2008 and newer vehicles.

Question 41: A 1976 gasoline passenger car is due for registration renewal in an enhanced area. It:

Is exempt because it is over 40 years old
Is subject to Smog Check (Correct answer)
Only needs a smog abatement fee
Is exempt as a classic

Correct answer: Is subject to Smog Check

Only 1975 and older gasoline vehicles are exempt, so a 1976 model is covered.

Question 42: If the emissions inspection system loses communication with the vehicle's OBD port during the test, what should the technician do?

Check the DLC connection, key position, and cable, then retry per prompts (Correct answer)
Pass the vehicle manually
Switch to a generic scan tool and enter results by hand
Fail the vehicle as a gross polluter

Correct answer: Check the DLC connection, key position, and cable, then retry per prompts

Communication failures are troubleshot and retried following inspection system prompts, never bypassed.

Question 43: Which characters are never used in a standard 17-character VIN to avoid confusion with numbers?

S, T, U
I, O, Q (Correct answer)
X, Y, Z
A, B, C

Correct answer: I, O, Q

I, O, and Q are excluded because they resemble 1 and 0.

Question 44: What is required before conducting the tailpipe test?

Warm engine to operating temperature (Correct answer)
Cool engine fully
Add new oil
Refill coolant

Correct answer: Warm engine to operating temperature

Before conducting a tailpipe emissions test, it is essential to ensure the engine is at its normal operating temperature. This allows the catalytic converter and other emission control systems to function efficiently and accurately, as they are designed to work best when hot. Testing a cold engine would yield inaccurate results, as the emission control systems would not be fully active, potentially leading to a false failure.

Question 45: Which cloud service model gives a customer virtual machines, storage, and networks while the customer manages the operating systems?

FaaS
IaaS (Correct answer)
SaaS
PaaS

Correct answer: IaaS

IaaS provides virtualized infrastructure, and the customer manages the OS and everything above it.

Question 46: In an engine change, the replacement engine must be:

Any model year if it passes the tailpipe test
Older than the vehicle chassis
Of a different fuel type for better economy
Same year or newer than the vehicle and from the same vehicle class (Correct answer)

Correct answer: Same year or newer than the vehicle and from the same vehicle class

Engine swaps must use an engine the same year or newer, of the same class, with all required emission controls.

Question 47: An engine has a turbocharger that wasn't on the factory configuration and no CARB EO. How should it be graded?

Fail as an illegally modified emission-related part (Correct answer)
Pass if the MIL is off
Note it but don't fail
Pass because it improves performance

Correct answer: Fail as an illegally modified emission-related part

Adding a non-factory, non-EO turbocharger changes the engine's emission configuration, so it fails the visual inspection.

Question 48: Which document verifies a technician’s smog certification status?

Smog certificate
Vehicle registration
Technician license or ID (Correct answer)
Shop insurance papers

Correct answer: Technician license or ID

A certified smog check technician must possess a valid license or identification issued by the relevant state agency, such as the Bureau of Automotive Repair (BAR) in California. This document serves as official verification of their qualifications and authorization to perform smog inspections. It ensures that only properly trained and approved individuals conduct these critical environmental tests.

Question 49: Which statement about virtualization's benefit to an organization is MOST accurate?

It removes the need for any physical hardware
It consolidates multiple workloads onto fewer physical servers, improving use of hardware (Correct answer)
It makes backups unnecessary
It guarantees that software never crashes

Correct answer: It consolidates multiple workloads onto fewer physical servers, improving use of hardware

Server consolidation is a main benefit because it uses hardware more efficiently and lowers costs.

Question 50: Why does the BAR OIS transmit inspection results to the Vehicle Information Database (VID) electronically?

To record results centrally and prevent altered or falsified certificates (Correct answer)
To update the vehicle's ECU calibration
To adjust the station's equipment calibration automatically
To reset readiness monitors remotely

Correct answer: To record results centrally and prevent altered or falsified certificates

Central electronic recording lets BAR verify inspections and detect fraud.

Question 51: While testing, a technician discovers a raw fuel leak in the engine compartment. What should be done?

Cover the leak and continue
Continue testing and note the leak
Stop the test because of the safety hazard (Correct answer)
Pass the vehicle if emissions are low

Correct answer: Stop the test because of the safety hazard

Unsafe conditions like fuel leaks must not be tested until corrected for the safety of people and equipment.

Question 52: Which OBD data item most directly helps BAR detect that the wrong vehicle was connected during an OBD inspection?

Engine coolant temperature
The OBD-reported VIN compared to the registered VIN (Correct answer)
Fuel tank level
Ambient air temperature

Correct answer: The OBD-reported VIN compared to the registered VIN

Most 2005+ vehicles report their VIN through OBD, which BAR compares with the vehicle's registration record.

Question 53: Which OBD generation became mandatory for all gasoline-powered light-duty vehicles sold in the United States starting with model year 1996?

OBD I
OBD III
EOBD
OBD II (Correct answer)

Correct answer: OBD II

OBD II became federally mandated for all 1996 and newer light-duty gasoline vehicles sold in the United States, standardizing diagnostic communication and readiness monitoring.

Question 54: Which of these protects the inspection station's local network best?

Using a firewall and changing the default router passwords (Correct answer)
Sharing one admin account among all staff
Turning off software updates to keep the system stable
Leaving Wi-Fi open so customers can connect easily

Correct answer: Using a firewall and changing the default router passwords

Firewalls and unique, non-default credentials lower the risk of unauthorized network access.

Question 55: Which record should a technician keep accurate to support an investigation if fraud is alleged?

Personal notes only
Complete and truthful inspection records (Correct answer)
Customer payment receipts only
Verbal statements

Correct answer: Complete and truthful inspection records

Accurate inspection records show what was tested and protect an honest technician during reviews.

Question 56: Why does the state inspection system tie every test record to a technician's unique login?

To create an audit trail and accountability for each inspection (Correct answer)
To let technicians share their workload anonymously
To calculate the technician's hourly wage
To speed up the emissions test

Correct answer: To create an audit trail and accountability for each inspection

A unique login means each recorded test can be traced to the licensed technician who performed it.

Question 57: How does Cryptography & Data Protection contribute to overall professional effectiveness?

It is relevant only during the certification examination
It provides essential knowledge and skills that directly impact quality of work and outcomes (Correct answer)
It applies only to supervisory-level professionals
It serves only as a credential requirement with no practical impact

Correct answer: It provides essential knowledge and skills that directly impact quality of work and outcomes

Cryptography & Data Protection directly contributes to professional effectiveness by providing essential knowledge and skills that improve the quality of work and outcomes across all career levels.

Question 58: An OBD scan shows the MIL commanded on with stored emissions-related DTCs. What is the inspection result?

Pass after clearing codes during the test
Incomplete, with certificate issued anyway
Fail (Correct answer)
Pass if tailpipe readings are acceptable

Correct answer: Fail

A commanded-on MIL indicates an active emissions fault and causes an OBD failure.

Question 59: An aftermarket engine tuner (ECU reflash) is legal for a California Smog Check vehicle only when it:

Is sold by a licensed dealer
Can be removed before the inspection
Raises fuel economy
Has a CARB Executive Order (EO) number (Correct answer)

Correct answer: Has a CARB Executive Order (EO) number

Emission-related aftermarket parts and software need a CARB Executive Order exemption to be legal.

Question 60: Which two technician license types replaced the Advanced Emission Specialist license in California?

Master Technician and Apprentice
STAR Technician and Referee
Test-Only and Test-and-Repair
Smog Check Inspector and Smog Check Repair Technician (Correct answer)

Correct answer: Smog Check Inspector and Smog Check Repair Technician

Since 2013, BAR issues separate Smog Check Inspector and Smog Check Repair Technician licenses.

Question 61: A snapshot of a virtual machine is mainly used to:

Compress the VM's network traffic
Move the VM's license to another user
Save the VM's state at a point in time so it can be rolled back later (Correct answer)
Permanently increase the VM's RAM

Correct answer: Save the VM's state at a point in time so it can be rolled back later

Snapshots capture a VM's state so administrators can return to it if something goes wrong.

Question 62: What does the term "clean piping" describe?

Cleaning carbon from the exhaust pipe before testing
Installing a CARB-approved muffler
Replacing the exhaust system with a new catalytic converter
Using a different, clean-running vehicle's exhaust to pass a tailpipe test (Correct answer)

Correct answer: Using a different, clean-running vehicle's exhaust to pass a tailpipe test

Clean piping is a fraudulent practice in which another vehicle's exhaust is sampled in place of the test vehicle's.

Question 63: Which inspection element is designed to catch a missing or modified EGR valve?

Headlight aim test
Tire tread check
Brake inspection
Visual inspection of emission control components (Correct answer)

Correct answer: Visual inspection of emission control components

The visual inspection checks that the required emission components, including EGR, are present, connected, and unmodified.

Question 64: What should be the first action when a new regulation is enacted that affects your practice?

Wait for enforcement before making changes
Review the regulation, assess its impact, and develop an implementation plan (Correct answer)
Assume existing procedures already comply
Delegate review to the newest team member

Correct answer: Review the regulation, assess its impact, and develop an implementation plan

When new regulations are enacted, professionals should promptly review them, assess their impact on current practices, and develop a structured implementation plan.

Question 65: Diesel-powered vehicles of which model years are subject to California Smog Check?

Only 2010 and newer
1998 and newer with GVWR of 14,000 lbs or less (Correct answer)
1975 and newer
All diesels regardless of year

Correct answer: 1998 and newer with GVWR of 14,000 lbs or less

Diesel vehicles 1998 and newer with a GVWR of 14,000 lbs or less require Smog Check.

Question 66: During an OBD inspection, the VIN reported by the vehicle's ECM does not match the VIN on the vehicle. What is the most likely concern?

Possible clean plugging or a replaced/tampered ECM (Correct answer)
Normal variation in OBD data
A loose gas cap
A weak 12-volt battery

Correct answer: Possible clean plugging or a replaced/tampered ECM

A mismatched ECM VIN can indicate that data is coming from another vehicle or that the ECM was swapped or altered.

Question 67: Which of these is an example of data 'at rest' that should be protected?

Inspection records stored on the station's hard drive (Correct answer)
A phone call with a customer
OBD data streaming from the vehicle during a test
Test results being uploaded to the state database

Correct answer: Inspection records stored on the station's hard drive

Data at rest is stored data, such as files on disk, as opposed to data moving over a network.

Question 68: What determines testing procedures for vehicles?

GPS history
VIN number alone
Vehicle specs like year and fuel type (Correct answer)
Color and trim

Correct answer: Vehicle specs like year and fuel type

Smog testing procedures are highly specific and are determined by a vehicle's unique specifications, including its model year, make, engine size, and fuel type. These characteristics dictate the applicable emissions standards and the type of test required, such as an On-Board Diagnostic (OBDII) check, a two-speed idle test, or a dynamometer test. This ensures appropriate and accurate assessment for each vehicle.

Question 69: Which law forms the statutory basis for California's Smog Check Program?

Federal Highway Act
California Penal Code only
California Labor Code
California Health and Safety Code (Correct answer)

Correct answer: California Health and Safety Code

The Smog Check Program is established in the Health and Safety Code, with regulations in Title 16 CCR.

Question 70: Which agency issues and processes vehicle registration that depends on a valid smog certificate?

DMV (Correct answer)
CARB
Caltrans
BAR

Correct answer: DMV

The DMV requires electronic smog certification before completing registration renewals and transfers.

Question 71: If an unlicensed employee performs a Smog Check using a licensed technician's login, who may face disciplinary action?

No one, if the vehicle actually passed
The licensed technician and potentially the station (Correct answer)
Only the unlicensed employee
Only the vehicle owner

Correct answer: The licensed technician and potentially the station

The licensed technician is responsible for inspections under their credentials, and the station can also be disciplined.

Question 72: Which BAR tool is used to collect and analyze Smog Check test data statewide to identify suspicious inspection patterns?

The DMV registration renewal notice
The vehicle's owner manual
The Vehicle Information Database (VID) (Correct answer)
The station's paper logbook

Correct answer: The Vehicle Information Database (VID)

Inspection results are transmitted to BAR's VID, where data analysis can flag fraudulent patterns.

Question 73: What is the function of the check valve in a secondary air injection system?

Regulate fuel pressure during cold start
Prevent exhaust gases from flowing back into the air pump and hoses (Correct answer)
Divert air to the atmosphere during deceleration
Meter crankcase vapors into the intake

Correct answer: Prevent exhaust gases from flowing back into the air pump and hoses

The one-way check valve lets air into the exhaust and blocks hot exhaust from flowing back and damaging upstream parts.

Question 74: Why is a functional check important during inspection?

To verify system operation (Correct answer)
To meet quotas
To compare models
To make the test longer

Correct answer: To verify system operation

A functional check during a smog inspection is critical to verify that the vehicle's emissions control systems are actively operating as designed. This includes checking components like the Malfunction Indicator Lamp (MIL), evaporative emissions system, and On-Board Diagnostic (OBD) system. It ensures that the vehicle is not only meeting tailpipe emissions at the time of the test but also continuously monitoring and controlling pollutants.

Question 75: A trailer is brought in for a Smog Check. The technician should know that trailers are:

Tested with a visual inspection only
Subject to inspection if over 10,000 lbs
Tested only with the towing vehicle
Exempt because they have no engine (Correct answer)

Correct answer: Exempt because they have no engine

Trailers have no engine or emissions system and are not part of the program.

Question 76: Which tool is used to retrieve emissions-related trouble codes?

Multimeter
Fuel gauge
Tire inflator
OBD-II scanner (Correct answer)

Correct answer: OBD-II scanner

An OBD-II (On-Board Diagnostics II) scanner is the standard diagnostic tool used to interface with a vehicle's onboard computer system. It allows technicians to retrieve diagnostic trouble codes (DTCs) related to emissions, view live sensor data, and check the status of various emission control systems. This tool is essential for identifying malfunctions that could cause a vehicle to fail a smog check.

Question 77: What is the relationship between Threat Detection & Incident Response and ethical professional conduct?

Ethics is relevant only when legal issues arise
There is no connection between technical knowledge and ethics
Ethical considerations are integrated into all aspects of professional practice in this area (Correct answer)
Ethics applies only to separate, unrelated decisions

Correct answer: Ethical considerations are integrated into all aspects of professional practice in this area

Ethical considerations are deeply integrated into Threat Detection & Incident Response, as professional conduct and integrity underpin all aspects of practice in this field.

Question 78: Which best describes the scope of Vulnerability Assessment & Penetration Testing in professional practice?

A theoretical framework with no practical applications
A comprehensive area covering both theoretical foundations and practical applications (Correct answer)
A narrow topic relevant only to entry-level professionals
An outdated concept no longer relevant to modern practice

Correct answer: A comprehensive area covering both theoretical foundations and practical applications

Vulnerability Assessment & Penetration Testing encompasses both theoretical foundations and practical applications that are essential to professional practice in this field.

Question 79: A customer's vehicle has modified engine software, and the customer asks the technician to 'just pass it.' What should the technician do?

Pass it if the tailpipe looks clean
Clear the codes and retest
Use another vehicle's ECU
Fail the vehicle as the software check requires (Correct answer)

Correct answer: Fail the vehicle as the software check requires

Unapproved software is tampering, and the inspection must record a failure.

Question 80: What is "clean plugging"?

Plugging vacuum leaks with sealant
Replacing spark plugs before an inspection
Connecting the OBD test cable to a different vehicle that will pass (Correct answer)
Clearing codes and immediately testing

Correct answer: Connecting the OBD test cable to a different vehicle that will pass

Clean plugging is fraud in which the OBD data of a passing vehicle is substituted for the test vehicle.

Question 81: Which item must be accurate in compliance reporting?

Window tint code
Vehicle nickname
Mileage only
VIN number (Correct answer)

Correct answer: VIN number

The Vehicle Identification Number (VIN) is a unique and critical identifier for every vehicle, making its accuracy paramount in compliance reporting. It ensures that smog test results are correctly linked to the specific vehicle, preventing errors and fraud. Accurate VIN reporting allows regulatory bodies to effectively track and manage emissions compliance across the vehicle fleet.

Question 82: What is the relationship between Vulnerability Assessment & Penetration Testing and ethical professional conduct?

Ethical considerations are integrated into all aspects of professional practice in this area (Correct answer)
Ethics is relevant only when legal issues arise
There is no connection between technical knowledge and ethics
Ethics applies only to separate, unrelated decisions

Correct answer: Ethical considerations are integrated into all aspects of professional practice in this area

Ethical considerations are deeply integrated into Vulnerability Assessment & Penetration Testing, as professional conduct and integrity underpin all aspects of practice in this field.

Question 83: What action must a smog technician take when a vehicle arrives for inspection with a flashing (blinking) MIL?

Proceed with the test but note the flashing light in the inspection report
Reset the MIL with a scan tool and retest to see if it illuminates again
Only fail the vehicle if P0300-range misfire codes are also stored
Immediately fail the vehicle, as a flashing MIL indicates active catalyst-damaging misfires (Correct answer)

Correct answer: Immediately fail the vehicle, as a flashing MIL indicates active catalyst-damaging misfires

A flashing MIL indicates active severe misfires that can damage the catalytic converter; the vehicle must be immediately failed and the owner directed to seek repair before testing.

Question 84: A technician writes their password on a sticky note attached to the inspection monitor. What is the main risk?

Anyone in the bay can use it to perform inspections under that technician's name (Correct answer)
The password will expire sooner
The OBD connection may fail
The monitor may overheat

Correct answer: Anyone in the bay can use it to perform inspections under that technician's name

An exposed password lets others impersonate the technician, who remains accountable for those records.

Question 85: A specially constructed vehicle (kit car) needing its first California registration must be inspected by:

Any licensed technician
A Smog Check Referee (Correct answer)
A STAR Test-Only station
The CHP

Correct answer: A Smog Check Referee

Specially constructed vehicles require a Referee inspection to establish their emissions certification.

Question 86: Which gas is specifically reduced by the EGR system?

Nitrogen oxide (Correct answer)
Oxygen
Hydrogen
Carbon dioxide

Correct answer: Nitrogen oxide

The EGR (Exhaust Gas Recirculation) system specifically targets the reduction of Nitrogen Oxides (NOx) emissions. By recirculating a small portion of inert exhaust gas back into the combustion chambers, it lowers peak combustion temperatures. High combustion temperatures are the primary cause of NOx formation, so reducing them directly minimizes the production of this harmful pollutant.

Question 87: Why should the inspection system software and operating system receive security updates promptly?

To patch known vulnerabilities that attackers could exploit (Correct answer)
To raise the analyzer's sampling rate
To change the emissions pass/fail standards
To delete old inspection records

Correct answer: To patch known vulnerabilities that attackers could exploit

Updates fix security flaws that attackers could otherwise exploit.

Question 88: Why can clearing DTCs just before a Smog Check hide problems?

It turns off the MIL for good
It updates the ECU calibration
It permanently repairs the fault
It resets the readiness monitors, so faults may not show up yet (Correct answer)

Correct answer: It resets the readiness monitors, so faults may not show up yet

Clearing codes resets the monitors to incomplete, which is why too many incomplete monitors cause a failure.

Question 89: A three-way catalytic converter controls which group of pollutants?

HC, CO, and CO2
CO, SO2, and particulates
HC, CO, and NOx (Correct answer)
NOx, O2, and CO2

Correct answer: HC, CO, and NOx

A three-way converter oxidizes HC and CO and reduces NOx at the same time.

Question 90: Which OBD II communication protocol became mandatory for all light-duty vehicles sold in the United States starting with model year 2008?

ISO 9141-2
SAE J1850 PWM
SAE J1850 VPW
ISO 15765-4 (CAN) (Correct answer)

Correct answer: ISO 15765-4 (CAN)

ISO 15765-4 (Controller Area Network/CAN) became the mandatory OBD II communication protocol for all light-duty US vehicles beginning with model year 2008, replacing older protocols.

Question 91: An aftermarket engine tuner with no CARB EO is plugged into the OBD port. What is the main concern?

It improves fuel economy legally
It only affects the radio
It is required for newer vehicles
The ECM calibration may have been illegally altered (Correct answer)

Correct answer: The ECM calibration may have been illegally altered

Non-exempted tuners can alter emissions calibrations, which is tampering.

Question 92: What happens to a Smog Check station that loses its license or is suspended?

It cannot perform official Smog Check inspections (Correct answer)
It can only perform tests on fleet vehicles
It can keep issuing certificates for 30 days
It can keep testing if a licensed technician is present

Correct answer: It cannot perform official Smog Check inspections

Both a valid station license and a licensed technician are required to perform official inspections.

Question 93: Why are motorcycles sometimes exempt from smog testing?

Low emissions and equipment limits (Correct answer)
They are expensive
Only one passenger
They’re newer models

Correct answer: Low emissions and equipment limits

Motorcycles are often exempt from smog testing due to their generally lower overall emissions compared to cars and trucks, attributed to their smaller engines and less frequent use. Additionally, the compact design of motorcycles can limit the space available for complex emissions control equipment and standardized testing ports. These factors lead to their exemption in many jurisdictions.

Question 94: What does a digital signature on transmitted data prove?

Who sent the data and that it was not altered (Correct answer)
That the data was compressed
That the data is publicly available
That the data was deleted after sending

Correct answer: Who sent the data and that it was not altered

Digital signatures provide authentication of the sender and verify data integrity.

Question 95: An aftermarket intake system has a valid CARB Executive Order number. What does this mean for the inspection?

It's only legal in off-road use
It needs a BAR referee inspection
It is legal for the vehicles listed in the EO and can pass (Correct answer)
It always fails

Correct answer: It is legal for the vehicles listed in the EO and can pass

A CARB EO exempts the part for the vehicles it lists, so it is not considered tampering.

Question 96: Why is the technician's license number recorded on each vehicle inspection report?

To identify who performed the inspection for accountability and audits (Correct answer)
For marketing purposes
To schedule the next oil change
To calculate sales tax

Correct answer: To identify who performed the inspection for accountability and audits

The license number links each report to the responsible technician for BAR oversight.

Question 97: A business keeps an identical copy of its systems in a second geographic cloud region in case the main region fails. This is mainly a strategy for:

Increasing keyboard speed
Disaster recovery and business continuity (Correct answer)
Lowering software license counts
Reducing monitor glare

Correct answer: Disaster recovery and business continuity

Replicating to another region lets services keep running or recover quickly after a regional outage.

Question 98: What is the purpose of the Low Pressure Fuel Evaporative Test (LPFET) on applicable older vehicles?

To test the fuel octane rating
To verify injector spray pattern
To measure fuel pump pressure
To check the fuel tank and evaporative system for vapor leaks (Correct answer)

Correct answer: To check the fuel tank and evaporative system for vapor leaks

LPFET pressurizes the evaporative system to detect leaks that release fuel vapors.

Question 99: A station's OIS shows an unexpected login at 2 a.m. under a technician's ID. What is the best first step?

Share the password with coworkers
Ignore it
Change the credentials and report the possible misuse to BAR (Correct answer)
Uninstall the OIS

Correct answer: Change the credentials and report the possible misuse to BAR

Securing compromised credentials and reporting the misuse protects the licensee and the program.

Question 100: Which ASM test mode is performed at 25 mph with a 25% dyno load?

FTP-75
ASM 5015
Two-Speed Idle
ASM 2525 (Correct answer)

Correct answer: ASM 2525

ASM 2525 runs at 25 mph with 25% of the FTP acceleration load.

Smog Check Technician Certification Exam

This certification is for technicians who perform smog checks and repairs on vehicles in California.

100

Questions

120 min

Time Limit

70%

To Pass

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Unanswered questions count as wrong — answer everything
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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

bar.ca.gov — Eligibility, score validity, late registration, renewal · verified Oct 2026
test-takers.psiexams.com — Test delivery, fees, exam format, retake fee, retake policy, score release, time limit, exam information · verified Oct 2026