Tahoe 4WD V8-393 6.5L DSL Turbo VIN S (1995)
Barometric Pressure Sensor: Description and Operation
EGR Control Pressure/BARO Sensor
OPERATION
On vehicles equipped with Exhaust Gas Recirculation (EGR), the EGR control pressure Barometric Absolute Pressure (BARO) sensor, mounted
on the left side of the cowl, is used to monitor the amount of vacuum in the EGR circuit. It senses the actual vacuum in the EGR vacuum line and
sends a signal back to the Powertrain Control Module (PCM). The signal is compared to the desired EGR calculated by the PCM. If there is a
difference in the PCM command and what is at the EGR valve sensed by the EGR control pressure/BARO sensor on vehicles not equipped with
EGR this sensor is used only to measure BARO, the PCM makes minor adjustments to correct.
When a major difference is sensed, the PCM recognizes a fault and sends a maximum EGR signal. This sensor is also used to measure barometric
pressure (BARO) under certain conditions, which allows the PCM to automatically adjust for different altitudes.
