The definitions in § 86.082-2 remain effective. The definitions listed in this section apply beginning with the 1984 model year.

Approach angle means the smallest angle in a plan side view of an automobile, formed by the level surface on which the automobile is standing and a line tangent to the front tire static loaded radius arc and touching the underside of the automobile forward of the front tire.

Axle clearance means the vertical distance from the level surface on which an automobile is standing to the lowest point on the axle differential of the automobile.

Breakover angle means the supplement of the largest angle, in the plan side view of an automobile, that can be formed by two lines tangent to the front and rear static loaded radii arcs and intersecting at a point on the underside of the automobile.

Curb-idle means:

(1) For manual transmission code light-duty trucks, the engine speed with the transmission in neutral or with the clutch disengaged and with the air conditioning system, if present, turned off. For automatic transmission code light-duty trucks, curb-idle means the engine speed with the automatic transmission in the Park position (or Neutral position if there is no Park position), and with the air conditioning system, if present, turned off.

(2) For manual transmission code heavy-duty engines, the manufacturer's recommended engine speed with the clutch disengaged. For automatic transmission code heavy-duty engines, curb idle means the manufacturer's recommended engine speed with the automatic transmission in gear and the output shaft stalled. (Measured idle speed may be used in lieu of curb-idle speed for the emission tests when the difference between measured idle speed and curb idle speed is sufficient to cause a void test under 40 CFR 1065.530 but not sufficient to permit adjustment in accordance with 40 CFR part 1065, subpart E.

Departure angle means the smallest angle, in a plan side view of an automobile, formed by the level surface on which the automobile is standing and a line tangent to the rear tire static loaded radius arc and touching the underside of the automobile rearward of the rear tire.

Emission-related maintenance means that maintenance which does substantially affect emissions or which is likely to affect the deterioration of the vehicle or engine with respect to emissions, even if the maintenance is performed at some time other than that which is recommended.

Heavy-passenger cars means, for the 1984 model year only, a passenger car or passenger car derivative capable of seating 12 passengers or less, rated at 6,000 pounds GVW or more and having an equivalent test weight of 5,000 pounds or more.

Non-emission related maintenance means that maintenance which does not substantially affect emissions and which does not have a lasting effect on the deterioration of the vehicle or engine with respect to emissions once the maintenance is performed at any particular date.

Scheduled maintenance means any adjustment, repair, removal, disassembly, cleaning, or replacement of vehicle components or systems which is performed on a periodic basis to prevent part failure or vehicle (if the engine were installed in a vehicle) malfunction, or anticipated as necessary to correct an overt indication of vehicle malfunction or failure for which periodic maintenance is not appropriate.

Special features enabling off-street or off-highway operation and use means a vehicle:

(1) That has 4-wheel drive; and

(2) That has at least four of the following characteristics calculated when the automobile is at curb weight, on a level surface, with the front wheels parallel to the vehicle's longitudinal centerline, and the tires inflated to the manufacturer's recommended pressure;

(i) Approach angle of not less than 28 degrees.

(ii) Breakover angle of not less than 14 degrees.

(iii) Departure angle of not less than 20 degrees.

(iv) Running clearance of not less than 8 inches.

(v) Front and rear axle clearances of not less than 7 inches each.

Static loaded radius arc means a portion of a circle whose center is the center of a standard tire-rim combination of an automobile and whose radius is the distance from that center to the level surface on which the automobile is standing, measured with the automobile at curb weight, the wheel parallel to the vehicle's longitudinal centerline, and the tire inflated to the manufacturer's recommended pressure.

Unscheduled maintenance means any adjustment, repair, removal disassembly, cleaning, or replacement of vehicle components or systems which is performed to correct a part failure or vehicle (if the engine were installed in a vehicle) malfunction which was not anticipated.

Useful life means:

(a) For light-duty vehicles a period of use of 5 years or 50,000 miles, whichever first occurs.

(b)(1) For a light-duty truck engine family or heavy-duty engine family, the average period of use up to engine retirement or rebuild, whichever occurs first, as determined by the manufacturer under § 86.084-21(b)(4)(ii)(B).

(2) For a specific light-duty truck or heavy-duty engine, the period of use represented by the first occurring of the following:

(i) The engine reaches the point of needing to be rebuilt, according to the criteria established by the manufacturer under § 86.084-21(b)(4)(ii)(C), or

(ii) The engine reaches its engine family's useful life.

(3) If the useful life of a specific light-duty truck or heavy-duty engine is found to be less than 5 years or 50,000 miles (or the equivalent), the useful life shall be a period of use of 5 years or 50,000 miles (or the equivalent), whichever occurs first, as required by section 202(d)(2) of the Act.

(4) For purpose of identification this option shall be known as the average useful-life period.

(c)(1) As an option for a light-duty truck engine family, a period of use of 12 years or 130,000 miles, whichever occurs first.

(2) As an option for a gasoline heavy-duty engine family, a period of use of 10 years or 120,000 miles, whichever occurs first.

(3) As an option for a diesel heavy-duty engine family, a period of use of 10 years or 120,000 miles, whichever occurs first, for engines certified for use in vehicles of less than 19,500 pounds GVWR; a period of use of 10 years or 200,000 miles, whichever occurs first, for engines certified for use in vehicles of 19,501-26,000 pounds GVWR; or, a period of use of 10 years or 275,000 miles, whichever occurs first, for engines certified for use in vehicles whose GVWR exceeds 26,000 pounds.

(4) As an option for both light-duty truck and heavy-duty engine families, an alternate full-life value assigned by the Administrator under § 86.084-21(b)(4)(ii)(B)(4).

(5) For purpose of identification these options shall be known as the assigned useful-life period options.

(6) For those light-duty truck and heavy-duty engine families using the assigned useful-life period options, the warranty period for emissions defect warranty and emissions performance warranty shall be 5 years/50,000 miles for light-duty trucks, 5 years/50,000 miles for gasoline heavy-duty engines and for diesel heavy-duty engines certified for use in vehicle of less than 19,501 lbs. GVWR, and 5 years/100,000 miles for all other diesel heavy-duty engines. However, in no case may this period be less than the basic mechanical warranty period.

(7) The assigned useful-life period options, as detailed in paragraphs (c)(1) through (c)(6) of this section, are applicable for the 1984 model year only.

(d)(1) As an option for the 1984 model year and for the 1984 model year only, the useful life of light-duty trucks and heavy-duty engine families may be defined as prescribed in § 86.077-2.

(2) For purpose of identification this option shall be known as the half-life useful-life option.