Respondent failed to comply with Section 203 of the Clean Air Act by removing the diesel exhaust fluid (DEF) tank, rendering the emissions control device inoperative, and by selling and/or installing off road kits that rendered inoperative the diesel particulate filter (DPF), exhaust gas recirculation (EGR), and selective catalytic reduction (SCR) systems and changed fuel timing or delivery and/or on-board diagnostics (OBD) parameters.