Whether the part qualifies under one of the part categories, listed in
§ 85.2122 of this subpart that are eligible to certify using emission critical parameters and, if so, whether the manufacturer elects to demonstrate certification using emission critical parameters. An aftermarket part may be certified under this category only if the part's emission-critical parameters, as set forth in
§ 85.2122, are equivalent to those of the original equipment or previously certified part it is to replace. Compliance with the emission-critical parameters discussed in
paragraph (b) of this section may be demonstrated by compliance with the relevant test procedures and criteria specified in appendix I to this subpart. The requirements of this paragraph apply to all on-road vehicles and engines. Alternatively, the manufacturer may elect to demonstrate certification compliance according to the emission test procedures described in
paragraph (c) of this section.