Diesel Regulations

All California-based fleets of two or more heavy-duty vehicles (gross vehicle rating over 14,000 pounds; except for 1998 and older, where the rating is over 6,000 pounds) are required to perform annual smoke and tamper inspections of their fleet.

Fleet owners are not required to inspect vehicles that are powered by diesel engines until after the 4th model year of the engine. (Example: 2020 engines were exempt from being tested for the PSIP until January 1 of 2024. A 2020 model-year engine must be tested sometime during 2024, or it will be in violation of PSIP).

To ensure compliance, the Air Resources Board will randomly audit fleets’ maintenance and inspection records and test a representative sample of vehicles.

All testing must conform to the Society of Automotive Engineers’ (SAE) J1667 snap-acceleration test procedure. All vehicles that do not pass the test must be repaired and retested. All testing must be performed using a SAE J1667 smoke meter. All testing records must be maintained for a period of two years.

For more information go to: http://www.arb.ca.gov/enf/hdvip/hdvip.htm

All heavy-duty trucks and buses are subject to California’s anti-smoke and tampering inspections. ARB inspectors may conduct unannounced roadside tests at various locales, such as:

• CHP weigh stations
• Randomly selected roadside locations
• Fleet facilities
• Border crossings

Poorly maintained engines emit excessive smoke. The best way to pass the test is to properly maintain your engine. Common maintenance problems are:

• Smoke puff limiters
• Maximum fuel rate too high
• Fuel pump calibration
• Fuel injection timing
• Air filter plugging

The “Roadside” Anti-Smoke Inspection will include the following:

• RPM Recording
• Snap Acceleration Test
• Visual Inspection
• Allowable levels of Smoke Opacity
  • All 1991 or newer engines: Must not exceed 40% smoke opacity
  • All pre-1991 engines: Must not exceed 55% smoke opacity
• Penalties for Excess Smoke include:

Notice of Violation (NOV): Issued to pre-1991 vehicles that have smoke opacities greater than 55% but less than 70% and have not received a citation in the past 12 months. Similar to a “fix-it-ticket”, the NOV has no penalty if repairs are made to the engine and proof is submitted to the ARB within 45 days. After 45 days, the NOV becomes a First Level Citation. Only one NOV may be issued to a pre-1991 vehicle within a 12-month period.

First Level Citation: Issued to pre-1991 engines with 70% or greater smoke opacity and 1991 and newer engines with greater than 40% opacity that have not received any citations in the past 12 months. The minimum penalty is $300 if engine repairs are made and proof of repair is submitted to the ARB within 45 days. After 45 days, the penalty increases to $800.

Second Level Citation: The penalty for any further violations within a 12 month period is $1800 for each violation. In addition, proof of repair must be submitted and the vehicle must be retested by the ARB in order to clear the citation.

In certain cases, the CHP may take a vehicle out of service for an outstanding citation if the penalty has not been paid, or if the vehicle has not been repaired. The DMV can place a hold on the CA registration renewal until the violation is cleared.

For more information go to: http://www.arb.ca.gov/enf/hdvip/hdvip.htm

Idling for more than 5 minutes is prohibited within California’s borders. As of January 1, 2008, this prohibition also applies to sleeper berth trucks during periods of sleep and rest. Idling under the following situations is acceptable:

• You are stuck in traffic.
• You are idling for inspecting or servicing your vehicle.
• You are operating a power take-off device.
• You cannot move because of adverse weather conditions or mechanical failure.
• You are queuing (must be beyond 100 feet away from any residential area).
• Your truck’s engine meets the optional NOx idling emission standard and your truck is located beyond 100 feet from any residential area.
• Written Idling Policy: As of March 1, 2009, medium and large fleets must also have a written idling policy that is made available to operators of the vehicles and informs them that idling is limited to 5 consecutive minutes or less.

The California Code of Regulations, title 13, §2183(c) requires that: “No 1974 or newer diesel powered heavy-duty commercial vehicle shall operate in California without evidence that, at the time of manufacture, the installed engine met emission standards at least as stringent as applicable federal emission standards for the model year of the engine (In the case of Mexican manufactured vehicles, Mexican and US EPA certified engines were equivalent in the 1994-2003 model years). The ARB shall base its determination on whether an engine meets the above requirement by inspecting the ECL affixed to the vehicle’s engine.” The ECL must be legible and maintained in the original location it was installed. The data on the label must correspond to the serial number stamped on the engine block (i.e. must be the correct label for the engine).

A vehicle owner found in violation of the above requirement is potentially subject to two distinct penalties: a) a tampered (missing) ECL carries a $300 penalty, and b) the regulation presumes that an engine without an ECL (or other documentation from the engine manufacturer) did not meet US EPA standards at the time of manufacture which carries a $500 penalty. If the $300 penalty and proof of corrective action are not provided within 45 days, a late penalty of $500 will be assessed.

Corrective action shall consist of:

• The engine manufacturer issuing a correct replacement ECL to their authorized dealer or distributor based on the engine serial number provided by the dealer or distributor.
• The authorized engine dealer or distributor affixing the replacement label at the location on the engine required by the engine manufacturer using the method specified by the engine manufacturer. Authorized dealers shall not allow vehicle owners to affix replacement labels – failure to comply with this may result in legal action.
• The owner of the cited vehicle submitting a photocopy or photo of the ECL and the installation invoice from the dealer to the ARB, including the vehicle identification number (VIN) and engine serial number.

For more information, go to: http://www.arb.ca.gov/enf/hdvip/hdvip.htm

“An on-road heavy-duty diesel or alternative-diesel vehicle operated in California may be subject to the California Air Resources Board Regulation to Reduce Particulate Matter and Criteria Pollutant Emissions from In-Use Heavy-Duty Diesel Vehicles. It, therefore, could be subject to exhaust retrofit or accelerated turnover requirements to reduce emissions of air pollutants.”

For more information go to: http://www.arb.ca.gov/dieseltruck