On-board diagnostic (OBD) systems monitor the performance of engine and aftertreatment components, including those responsible for controlling emissions. The OBD system is designed to help ensure proper operation of the emission control equipment, alerting the driver in case of malfunctions, so that vehicles meet emissions limits during everyday use. OBD systems are a valuable tool for vehicle owners and technicians, as they supply important feedback about engine maintenance needs and point toward potentially urgent repairs. OBD assists in the service and repair of vehicles by providing a simple, quick, and cost-effective way to identify problems by retrieving vital automobile diagnostics data. OBD systems are also a vital component of inspection and maintenance programs for reducing in-use emissions and cutting down on high-emitting vehicles.
On-board diagnostics for heavy-duty vehicles (HDVs) were first introduced in 2005 in Europe. The U.S. Environmental Protection Agency began to phase in OBD requirements between 2005 and 2008. California matched the phase-in schedule of EPA’s HDV OBD program.
Other countries have adopted HDV OBD requirements following the European program model. India adopted OBD requirements for its Bharat IV emission standards starting in 2013. Brazil has adopted OBD requirements similar to Euro IV/V since 2012 for its PROCONVE P-7 HD standards. China requires European OBD as part of the China IV HDV standards since July 2013.
This white paper describes the OBD deployment schedule and monitoring requirements for HDVs in Brazil, China, Europe, India, and the United States (EPA and California’s Air Resources Board). Given that Brazil, China, and India follow the European model, this analysis focuses on the European OBD regulations and then checks for differences in the implementation in Brazil, China, and India. The implementation schedules are presented first, then the thresholds and monitoring requirements are tabulated; the final section focuses on the measures for proper nitrogen oxide control measures on vehicles equipped with selective catalytic reduction.