Circuit Operation

A 5-volt reference voltage is supplied to the barometric pressure sensor power terminal (terminal No. 1) from the PCM (terminal No. 97). The ground terminal (terminal No. 5) is grounded with PCM (terminal No. 88). A voltage that is proportional to the atmospheric pressure is sent to the PCM (terminal No. 100) from the barometric pressure sensor output terminal (terminal No. 2).