Mileage Calibration Switch: Description and Operation
PURPOSEBecause 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. With switch input, the ECU compensates for engine condition changes by altering distribution of secondary air in a manner designed to both reduce emissions and extend service life of components such as catalytic converters and oxygen sensor.
LOCATION
With speedometer in instrument cluster.
OPERATION
Switch is "OFF" below 20,000 miles (34,000 km), and "ON" above. When switch is "OFF," ECU signal at terminal 1N is below 1.5V. When switch is "ON," signal is battery voltage.