Manuals through 2025 now available!
Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.
LEMON is the spiritual successor to CHARM, I recommend you try it!
Link:
lemon-manuals.la or
lemon-manuals.org.ua
(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)
Or, hide this message:
temporarily or
permanently
Barometric Pressure Sensor: Description and Operation
The barometric pressure sensor is one of three sensors that make up the Volume Air Flow
(VAF) sensor. The barometric pressure sensor is essentially a strain gauge used to measure atmospheric pressure. Inside the sensor is a metal diaphragm with a small wire attached. The diaphragm flexes according to changes in atmospheric pressure. When the diaphragm flexes, the wire attached to it stretches, changing the resistance of the wire. The Engine Control Module
(ECM) applies five volts to the barometric pressure sensor and measures the voltage drop across the sensor. Sensor output is in volts and as atmospheric pressure decreases (higher altitudes), the voltage drop across the sensor increases.