Pump - Air: Operation

The electric air pump only functions during cold starts. The PCM will not command the electric air pump to run if the engine coolant temperature is more than 10°Celsius (50°Fahrenheit) than ambient temperature, and when the coolant temperature is greater than 37°Celsius (98.6°Fahrenheit). The amount of time the pump will run is based on the amount of air flowing into the system. The amount of air flowing into the system is measured by a mass air flow sensor located at the air inlet tube. The maximum time the electric air pump will run is for 18 seconds.