Barometric Pressure Sensor: Description and Operation
This solenoid, which is controlled by Logic Module or SMEC, is located in the MAP sensor line. The solenoid measures barometric pressure at closed throttle, once per throttle closure, but no more than once every 30 seconds for 1984-87 models or 3 minutes for 1988-89 models and below a specified RPM. The barometric information is used primarily for boost control.