Idle Exhaust Emissions Test. A vehicle shall fail if sample dilution occurs. Hydrocarbon (HC) and carbon monoxide (CO) emissions may not exceed the following values: Table 2. Gross vehicle weight greater than 8,500 pounds but less than or equal to 10,000 pounds. Table 3. Gross vehicle weight greater than 10,000 pounds: Gas Cap Leak Test. A vehicle shall fail if the gas cap is missing, broken, or the wrong style for the vehicle. The gas cap leak rate may not exceed 60 cubic centimeters per minute at a pressure of 30 inches of water column. On-Board Diagnostics Test. A vehicle shall fail if a component of the on-board diagnostics system is missing or damaged. Standards for the on-board diagnostics test are specified in 40 CFR §85.2207 and 40 CFR §85.2222.