[EPA press release - June 4, 1973]

The Environmental Protection Agency today set regulations requiring warning systems, such as dashboard lights or buzzers, on 1975 and later model cars to alert drivers to malfunctions or the need for maintenance on certain air pollution control systems.

Installation of the warning systems will be required if certain emission control systems are expected to require maintenance during the vehicle's useful life, defined as 50,000 miles by the Clean Air Act. The new regulations specify the conditions under which manufacturers will be allowed to perform maintenance on their certification test vehicles which are required to be operated for 50,000 miles. These vehicles are tested to determine compliance with Federal auto emission standards.

The warning systems are designed to help insure that the same maintenance is performed by car owners as that performed during the certification tests. Such warning devices are necessary because malfunctions on certain emission control systems (catalytic converters and exhaust gas recirculation systems) may not be otherwise evident to the driver.

The regulations allow scheduled maintenance on the test vehicles, such s periodic tune-ups, and unscheduled maintenance, such as replacement of a misfiring spark plug, to be performed under specified conditions.

The regulations also allow the replacement or servicing of catalytic converters once during the 50,000 mile durability run if the need for such maintenance is indicated by the warning system. Catalytic converters are muffler-like devices which many manufacturers have adopted as the primary means of air pollution control.

Another principal means of emission control, the exhaust gas recirculation system, may be serviced up to three times during the 50,000 miles if a suitable warning system is provided.

Three major engine tune-ups on test cars are allowed at minimum intervals of 12,500 miles. According to recent studies, the average mileage interval between major engine tune-ups on cars now on the road is approximately 12,500 miles.

The owner's manual must set forth each specific model's maintenance requirements and explain the warning device's operation. Under the new regulations, the EPA Administrator can disallow any vehicle maintenance if the warning devices can be easily disconnected or do not provide sufficient notice to the driver of the need for maintenance.

Under the Clean Air Act of 1970, all new vehicles sold in the United States must be certified as meeting EPA auto emission standards and are therefore subject to the maintenance regulations.

The new regulations are published in today's Federal Register.