Common Emission Control System (ECS) Abbreviations
Component Name
Abbreviation
Exhaust Gas Recirculation
EGR
Cooled EGR
EGR-C
Charge Air Cooler
CAC
Diesel Oxidation Catalyst
DOC
Engine/Powertrain Control Module
ECM/PCM
Throttle body fuel injection
TBI
Indirect/Direct Diesel Injection
IDI/DDI
Sequential/multi port injection
SFI/MFI
Diesel Particulate Filter
DPF
Periodic Trap Oxidizer
PTOX
Turbocharger/Supercharger
TC/SC
Heated/Oxygen Sensor
HO2S/02S
Three-way/Oxidizing Catalyst
TWC/OC
Pulsed/Secondary Air Injection
PAIR/AIR
Smoke Puff Injector
SPL
Ammonia Oxidation Catalyst
AMOX
Selective Catalyst Reduction-Urea
SCR-U
SCR-Ammonia
SCR-N
Engine Modification
EM
FAQs
CARBTest service appointments will only be
available in specific vehicle circumstances. The following are some reasons why you would make a CARBTest
service appointment:
You received a CARB notification requiring your vehicle to have CARBTest inspection.
Credentialed testers are not available for testing your vehicle.
The vehicle engine has been changed.
Your vehicle has been retrofitted with an alternative fuel system (natural gas, propane, ethanol,
methanol, or other non-diesel or non-gasoline fuel, and includes any of these fuels used in combination
with each other).
You would like to apply for a part unavailability compliance time extension due to the
unavailability of the necessary part(s) to repair your vehicle to demonstrate Clean Truck Check
compliance,
You have recently converted your vehicle to motorhome.
You would like to dispute an inspection result and request an independent evaluation of a vehicle’s
compliance status.
You believe your vehicle was improperly tested.
You believe your vehicle was inappropriately failed.
You believe your vehicle failed a Clean Truck Check inspection for missing emission control
equipment that is not required.
You have a dispute over the type of inspection performed (smoke opacity, visual, OBD).
Your vehicle’s condition makes it incompatible with CARB Clean Truck Check test procedures due to
unusual vehicle configurations, design, or other inspection incompatibility.
Is this CARBTest program the same as the Smog Check Referee Program operated by the Bureau of Automotive Repair?
No. This CARBTest (California Air Resources Board Truck Emission Systems Testing) program is
specifically for the California Clean Truck Check that is applicable to all heavy-duty non-gasoline
vehicles with gross vehicle weight ratings (GVWR) greater than 14,000 pounds operating in California.
How can I speak to the CARBTest directly?
If you have a specific question(s) that you need to discuss directly with a CARBTest
representative, please fill out an online form
here. Our CARBTest representative will respond to your question
via email or phone call.
I received a citation for vehicle emissions and I was told to see a CARBTest. Can the CARBTest clear the citation?
The CARBTest can ONLY inspect the vehicle to determine if the vehicle passes the required inspection.
Once the vehicle has passed the CARBTest, you will need to complete the process of clearing the citation
with the issuing agency or court system. Please refer to your citation for this information.
Can someone else take my vehicle to the appointment?
Yes. Anyone you choose can bring the vehicle to the appointment as long as they bring the vehicle and the
required paperwork.
How soon can I find out if my vehicle passed the CARBTest inspection?
Upon completion of the inspection, the CARBTest tester will review the results with you.
Can the CARBTest help me to make emissions-related repairs?
No. The CARBTest tester does NOT perform repairs or diagnostic tests, but they can help you to
understand what repairs are necessary in order for the vehicle to pass the Clean Truck Check compliance
test.
What should I bring to my CARBTest appointment?
You will be provided with a list of what to bring when you schedule your appointment. Generally, you
will be required to bring with you all the documents that were submitted during your CARBTest
appointment request process. These may include CARB notification, related citations, DMV documents,
vehicle repair invoice/paperwork, etc.
Read more about preparing for your appointment.
Can I still make a CARBTest appointment if my vehicle is in poor operating condition?
Your vehicle must be in a safe and fully functional operating condition in order for the CARBTest to
inspect the vehicle. Be sure that the oil is full, the vehicle is not overheating, etc. Some of the
reasons the CARBTest may not be able to inspect the vehicle include:
Low oil level
Fuel leak
Coolant leak
Excessive oil leak
How long does a CARBTest appointment usually take?
Appointments are scheduled for 50 minutes. Some service may require a longer time. The CARBTest tester
will inform you beforehand if your CARBTest appointment is anticipated to be more than 50 minutes.
What if my vehicle does not pass the CARBTest inspection?
If your vehicle does not pass a CARBTest inspection, the CARBTest tester will provide you with a CARBTest
Vehicle Inspection Report containing guidance on how to resolve the issue. Please remember that the
tester cannot perform diagnostics or repairs.
News
The California Air Resources Board is Beginning to Roll out the
Clean
Truck Check
What is Clean Truck Check?
Passenger vehicles and lighter trucks have been required to undergo periodic emissions testing
and
reporting for decades through the Bureau of Automotive Repair’s Smog Check Program. Now under
the
California Air Resources Board’s (CARB) Clean Truck Check, big trucks and other heavy-duty
vehicles
traveling on California’s roadways will be subject to similar requirements to ensure polluting,
poorly maintained heavy-duty vehicles operating in California are quickly identified and
repaired.
The Clean Truck Check will provide significant reductions in smog-forming and carcinogenic toxic
air
pollution necessary to achieve federal air quality mandates and healthy air in California’s
communities.
What Type of Vehicles are Subject to the Clean Truck Check?
Nearly all diesel and alternative fuel heavy-duty trucks and buses with a gross vehicle weight
rating
(GVWR) over
14,000 pounds that operate in California are subject to the Clean Truck Check. This includes
hybrid
trucks and buses, commercial vehicles, privately-owned vehicles, motorhomes, government
vehicles,
and vehicles registered outside of California.
When Does the Clean Truck Check Start?
The first phase of the Clean Truck Check implementation began in January 2023 with the use of
roadside emissions monitoring devices (REMD) to screen for vehicles that may have high
emissions.
Vehicles flagged as potential high emitters may be required to undergo follow-up vehicle
compliance
testing to ensure they are operating with properly functioning emissions control systems. When
fully
implemented in the 2024 timeframe, the Clean Truck Check will require most heavy-duty vehicles
operating in California (including out-of-state vehicles) to undergo twice per year periodic
compliance testing.
Who Can Perform Clean Truck Check Compliance Testing?
Clean Truck Check compliance testing must be performed by a credentialed tester who has
completed
the CARB’s free, online Tester Training Course available at
Tester Training Course and Exam | California Air Resources Board
and passed the accompanying examination.
Where Do I Get Additional Clean Truck Check Information?