(a) The standard-setting part requires as a condition of certification that engines with adjustable parameters meet all the requirements of the standard-setting part for any setting in the practically adjustable range. This section defines these terms and describes general provisions that apply broadly across sectors. This section refers to engines, because most adjustable parameters are integral to the engine even in the case of equipment-based standards; this section also applies for equipment-based adjustable parameters. The provisions of this section apply starting with model year 2027 and are optional for earlier model years.

(b) You must use good engineering judgment for all decisions related to adjustable parameters. We recommend that you ask for preliminary approval for decisions related to new technologies, substantially changed engine designs, or new methods for limiting adjustability. The standard-setting part describes the information you must include in the application for certification related to adjustable parameters. Decisions related to adjustable parameters include the following:

(1) Determining which engine operating parameters qualify as adjustable parameters.

(2) Establishing the adequacy of the limits, stops, seals, programming limits, inducements, or other means used to limit adjustment, limit reprogramming, or ensure replenishment.

(3) Defining the practically adjustable range for each such parameter.

(c) For purposes of this section, “operating parameter” means any feature that can, by the nature of its design, be adjusted to affect engine performance. For example, while bolts used to assemble the engine are practically adjustable (can be loosened or tightened), they are not adjustable parameters because they are not operating parameters. Consider all programmable parameters not involving user-selectable controls to be a single, collective operating parameter.

(d) Operating parameters are considered adjustable parameters if they are practically adjustable by a user or other person by physical adjustment, programmable adjustment, or regular replenishment of a fluid or other consumable material. However, an operating parameter is not an adjustable parameter if—

(1) We determine it is permanently sealed or it is not practically adjustable using available tools, as described in paragraph (e) of this section; or

(2) We determine that engine operation over the full range of adjustment does not affect emissions without also degrading engine performance to the extent that operators will be aware of the problem.

(e) An operating parameter is considered practically adjustable as follows:

(1) Physically adjustable parameters are considered practically adjustable if the adjustment is accessible and can be performed by an experienced mechanic using appropriate tools within the following time and cost thresholds, excluding extraordinary measures:

(i) For engines at or below 30 kW, physically adjustable parameters are considered practically adjustable if a typical user can make adjustments with ordinary tools within 15 minutes using service parts that cost no more than $30.

(ii) For 30-560 kW engines, physically adjustable parameters are considered practically adjustable if a qualified mechanic can make adjustments with ordinary tools within 60 minutes using service parts that cost no more than $60.

(iii) For engines above 560 kW, physically adjustable parameters are considered practically adjustable if a qualified mechanic can make adjustments with any available supplies and tools within 60 minutes.

(iv) Cost thresholds in this section are expressed in 2020 dollars. Adjust these values for certification by comparing most recently available Consumer Price Index for All Urban Consumers (CPI-U) value published by the Bureau of Labor Statistics at www.bls.gov/data/inflation_calculator.htm.

(v) Cost thresholds do not include the cost of labor or the cost of any necessary tools or nonconsumable supplies. Time thresholds refer to the time required to access and adjust the parameter, excluding any time necessary to purchase parts, tools, or supplies, or to perform testing.

(vi) The term “ordinary tools” has the following meanings for different sizes of engines:

(A) Ordinary tools consist of slotted and Phillips head screwdrivers, pliers, hammers, awls, wrenches, electric screwdrivers, electric drills, and any tools supplied by the manufacturer, where those tools are used for their intended purpose.

(B) For 30-560 kW engines, ordinary tools includes the tools identified in paragraph (e)(1)(vi)(A) of this section and any other hand tools, solvents, or other supplies sold at hardware stores, automotive parts supply stores or on the internet.

(vii) The following extraordinary measures are not included when determining whether a physically adjustable parameter is considered “practically adjustable” according to the specified time and cost thresholds:

(A) Removing the cylinder head(s) from the engine block.

(B) Fully or partially removing a carburetor.

(C) Drilling or grinding through caps or plugs.

(D) Causing damage to engine or equipment if the associated repair would exceed the time or cost thresholds in this paragraph (e)(1).

(E) Making special tools to override design features that prevent adjustment. Note that extraordinary measures do not include purchase of such special tools if they become available as described in paragraph (e)(1)(vi)(B) of this section.

(2) A programmable operating parameter is considered “practically adjustable” if an experienced mechanic can adjust the parameter using any available tools (including devices that are used to alter computer code). Conversely, such parameters are not practically adjustable if you limit access to electronic control modules with password or encryption protection. You must have adequate protections in place to prevent distribution and use of passwords or encryption keys. This paragraph (e)(2) applies for engines with any degree of programmable control. Programmable settings are considered practically adjustable if any of the following apply:

(i) The user can make the adjustment by following instructions in the owners manual.

(ii) An experienced mechanic can make the adjustment using ordinary digital interface tools for selecting available settings or options as described in this paragraph (e)(2).

(f) The practically adjustable range for physically adjustable operating parameters is based on design features to create physical limits or stops to limit adjustment. A physical limit or stop is adequate for defining the limits of the practically adjustable range if it has the following characteristics:

(1) In the case of a threaded adjustment, the head is sheared off after adjustment at the factory or the threads are terminated, pinned, or crimped to prevent additional travel without causing damage for which the repair would exceed the time or cost thresholds in paragraph (e)(1) of this section.

(2) In the case of fasteners, bimetal springs, or other mechanical devices used to limit adjustment, those devices are recessed within a larger, permanent body and sealed with a plug, cap, or cover plate that limits access to the device consistent with the time and cost thresholds in paragraph (e)(1) of this section.

(3) Operators cannot exceed the travel or rotation limits using appropriate tools without causing damage for which the repairs would exceed the time or cost thresholds specified in paragraph (e)(1) of this section. For example, if a vehicle has a shim, bushing, or other device to limit flow rates, range of travel, or other parameters to prevent operating outside of a specified range of engine or vehicle speeds, you must take steps to prevent operators or mechanics from removing, replacing, or altering those parts to operate at a wider range of engine or vehicle speeds.

(g) Apply the following provisions to determine the practically adjustable range for programmable parameters that can be adjusted by changing software or operating parameters (“reflashed”):

(1) If an engine includes multiple operating modes or other algorithms that can be selected or are easily accessible, consider each of the selectable or accessible modes or settings to be within the practically adjustable range.

(2) If you sell or offer to sell software or other tools that an experienced mechanic not affiliated with the manufacturer could use to reflash or otherwise modify the electronic control module, consider all those settings to be within the practically adjustable range.

(3) The following systems and features illustrate examples of the types of programmable settings for which this paragraph (g) applies:

(i) Air-fuel setpoints for closed-loop fuel systems.

(ii) Reductant flow systems.

(iii) Base maps for fuel injection or spark timing.

(iv) Exhaust gas recirculation maps.

(h) The following provisions apply for adjustable parameters related to elements of design involving consumption and replenishment, such as DEF tank fill level and hybrid battery state of charge:

(1) We will determine the range of adjustability based on the likelihood of in-use operation at a given point in the physically adjustable range. We may determine that operation in certain subranges within the physically adjustable range is sufficiently unlikely that the subranges should be excluded from the allowable adjustable range for testing. In such cases, the engines/equipment are not required to meet the emission standards for operation in an excluded subrange.

(2) Shipping new engines/equipment in a state or configuration requiring replenishment to be within the range of adjustability for a certified configuration does not cause a violation of the prohibition in § 1068.101(a)(1).

(i) We will make determinations regarding in-use adjustments of adjustable parameters under this section for certifying engines as follows:

(1) Our determinations will depend on in-use maintenance practices conforming to the maintenance and service information you provide. For example, if your published maintenance instructions describe routine procedures for adjusting engines or if you or your dealers make specialized tools available to operators, we will conclude that such adjustments are likely to occur. Also, your maintenance and service information may not specify adjustable ranges that are broader than those that you specify in your application for certification.

(2) We may review manufacturer statements under this section for certifying engines for a later model year if we learn from observation of in-use engines or other information that a parameter was in fact practically adjustable or that the specified operating range was in fact not correct. We may require you to include a new adjustable parameter or to revise your specified operating range for an adjustable parameter.

(j) We may inspect your engines at any time to determine whether they meet the specifications of this section. We may purchase engines for testing, or we may ask you to supply engines for such inspections. We will inspect using appropriate tools and time limits and using any available devices that alter computer code, as specified in paragraph (e)(2) of this section. The inspection will determine the following:

(1) If the adjustable parameter is limited to the adjustable range specified in the manufacturer's certification application.

(2) If physical stops for physically adjustable parameters can be bypassed using methods outlined in paragraph (f) of this section.

(k) Except as provided in the standard-setting part and this paragraph (k), engines are not in the certified configuration if you produce them with adjustable parameters set outside the range specified in your application for certification. Similarly, engines are not in the certified configuration if you produce them with other operating parameters that do not conform to the certified configuration. Where we determine that you failed to identify something that should be considered an adjustable parameter, we may require you to treat the parameter as defective under § 1068.501. If we determine you deliberately misrepresented the accessibility of the parameter or that you did not act in good faith, we may take action regarding your certificate as described in the standard-setting part (see, for example, 40 CFR 1054.255).

(l) Nothing in this section limits the tampering prohibition of § 1068.101(b)(1) or the defeat device prohibition of § 1068.101(b)(2).