The California Air Resources Board has adopted new regulations for On-Board Diagnostic (OBD) systems for Heavy-Duty Engines for the 2010 and subsequent model years. The new section is CCR 13 Section 1971.1.
OBD systems help to ensure that vehicles maintain low emissions throughout the life of the vehicle. California recently adopted diagnostic system requirements for heavy-duty vehicles (GVWR greater than 14000 pounds). Oxides of nitrogen and particulates emitted from heavy-duty trucks, especially diesel trucks are of great concern. Oxides of nitrogen are a pre-cursor to ozone as well as a lung irritant, and particulates are carcinogenic and have been identified as a toxic air contaminant. More stringent emission standards for heavy-duty vehicles will be phased in during 2007 - 2008.
Emission related malfunctions can cause vehicle emissions to increase well beyond the standards that they are intended to meet, therefore regulations have been previously adopted to require Engine Manufacturer Diagnostic Systems (EMD) to be installed on all 2007 and subsequent heavy-duty engines. The EMD regulations are much less comprehensive than the OBD regulations applicable to light and medium-duty vehicles because it only requires the monitoring of a few major emission sources and contains no standardised requirements. The EMD regulation was initially developed to ensure that all heavy-duty engine manufacturers implemented a basic diagnostic system for the major emission sources; later more stringent regulations would be phased-in.
This new section 1971.1 requires more comprehensive diagnostic, testing and standardization procedures for future heavy-duty engines. The OBD systems are to be phased-in starting with the 2010 model on-road heavy-duty engines (GVWR greater than 14000 pounds) sold in California. Manufacturers are required to monitor virtually every emission-related component and system on the engine and to indicate a malfunction before the emissions exceed a specified threshold. The regulations also define the content and format of the diagnostic information required.