(1) All persons testing gasoline vehicles shall, as directed by ecology, either:

(a) Connect the OBD testing equipment to determine what diagnostic codes may be commanding the check engine light on and whether each emission related monitor is ready to report; or

(b) Follow the two-speed idle exhaust emission testing procedures described in Appendix B-Test Procedures of Subpart S-Inspection/Maintenance Program Requirements of Part 51 of chapter 1, Title 40 of the Code of Federal Regulations adopted November 1, 1992.

(2) Ecology may require variations to the testing procedures to accommodate the design of certain vehicles.