California agency mandates onboard diagnostics by 2010

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The California Air Resources Board has adopted a rule that requires heavy-duty engine makers to install systems that diagnose failing emission control components.

“We expect this rule to lead to lower emissions due to more durable equipment on big rigs and faster repairs on damaged or broken emission control equipment,” said Cindy Tuck, ARB chair. “Easier diagnosis will also cut costs for vehicle owners.”

ARB estimates the regulation will reduce nitrogen oxide emissions from on-road heavy-duty trucks and buses by nearly 110 tons per day by 2020. The rule is set for introduction in 2010, with full compliance by 2016.

It requires equipment that will monitor 120 engine locations that can leak emissions as they age. It also requires manufacturers of heavy-duty diesel and gasoline-powered trucks and buses to equip those vehicles with a system of sensors that can monitor the performance of engine parts that may affect emissions.

The monitors are designed to alert vehicle operators, via a dashboard indicator light, that part of the pollution control system is failing. An access port under the dash allows a mechanic with a handheld computer to obtain detailed information about the vehicle’s performance and the malfunctioning component.

The program is similar to one in operation on light- and medium-duty vehicles since 1996 in California. More than 120 million cars, SUVs and light and medium trucks nationwide are equipped with onboard diagnostic equipment.

ARB is a department of the California Environmental Protection Agency.