What does a Barometric Pressure Sensor do for your engine?
The BARO sensor reads the barometric pressure. The PCM uses this information to make adjustments to fuel trim and engine timing. The engine requirements are quite different when driving in San Diego at sea level as compared to Denver at 5,000 feet.
Where are these sensors located?
Standalone BARO sensors are typically mounted on the fire-wall or the inside fender skirt. Late model BARO sensors are incorporated into the MAP sensor, and may be mounted on the intake manifold.
Will a malfunctioning Barometric Pressure Sensor illuminate the check engine light or affect vehicle operation?
Yes, a failing sensor can illuminate the MIL, and may cause drivability problems such as stumbling, stalling and sluggish acceleration.
What are the common causes of failure?
Typically these sensors fail due to exposure to the elements as the result of mounting location.
How to determine if these sensors are malfunctioning?
The BARO sensor can be checked with a scan tool by comparing the scan tool read out to the local barometric reading. Standalone Ford sensors require a special tool to determine if the sensor is functioning properly. The ECM will set DTC P0105 when there is an open or short in the BARO circuit. There is a Fail-Safe strategy that turns on when this code is detected. The PCM uses a predetermined ignition timing and AF trim to maintain emission levels.
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