Mileage Calibration Switch: Description and Operation

Mileage Sensor (No. 1 And No. 2):

Because of unique problems (such as oil injection) associated with controlling rotary engine emissions, Mazda incorporates a secondary air injection system with performance characteristics that vary with vehicle mileage. A mileage sensor, located in the speedometer assembly, is "OFF" below 20,000 miles (34,000 km) and "ON" above. With this input, the ECU compensates for engine condition changes by altering the distribution of secondary air in a manner designed to both reduce emissions and extend the service life of components such as catalytic converters and oxygen sensors.