Prelude L4-2.2L SOHC (1994)
Barometric Pressure Sensor: Description and Operation
DESCRIPTION
The Barometric Pressure (BARO) Sensor, built into the Programmed Fuel Injection Electronic Control Module (PGM-FI ECM), senses changes
in altitude so that ignition timing and fuel delivery can be adjusted to maintain consistent engine performance.
OPERATION
The PGM-FI ECM supplies a 5.0 volt signal and a ground to the sensor. Changes in the pressure differential between the sealed cavity and the
atmosphere cause the silicon to flex. The flexing of the silicon generates a small voltage which is amplified by the support circuitry and used to
modify the fixed 5.0 volt signal supplied by the PGM-FI ECM. The modified signal is then read by the PGM-FI ECM.