When a high-flow catalytic converter or test pipe is used on a late model car it's guaranteed that CEL (Check Engine Light) will come on. This CEL is caused by a fault code that indicates an inefficient catalytic converter. \n \nOur CEL eliminator is CNC machined in-house from high quality cold roll steel for a long-lasting effective performance. \n \nInstall this spacer on your REAR (downstream; post-cat) oxygen sensor to effectively remove the code for catalyst efficiency. This is recommended for vehicles that do NOT have "stage 2" software. \n \nThis product is not intended to and will not provide emissions compliance. FOR OFF-ROAD USE ONLY! \nEmissions laws vary by state and by province. Check local and federal laws before modifying your exhaust system. \nEmissions compliance is the sole responsibility of the vehicles owner. \n \nThis is a universal product that works on variety of vehicles; however it is not effective on some cars. \n \nThis product is not intended to and will not provide emissions compliance. \n \nEmissions laws vary by state. Check local and federal laws before modifying your exhaust system. \n \nEmissions compliance is the sole responsibility of the owner. \n \nNOTE: This part does not guarantee that the CEL will turn off.