The barometric sensor, also commonly known as the barometric air pressure sensor (BAP), is a type of engine management sensor commonly found on many vehicles. It is responsible for measuring the atmospheric pressure of the environment that the vehicle is driving in. Different environments will have different atmospheric pressures, which will have an affect on how the vehicle runs. High altitudes will have thinner air, which means less oxygen for the engine during the intake strokes, which will require a different amount of fuel.
The BAP is similar to the engine MAP sensor. However, the BAP measures the pressure outside of the engine, while the MAP measures the pressure inside of the manifold. The computer will often interpret data from both sensors to determine the best timing and fuel conditions for optimum engine performance. For this reason, when BAP sensors fail, they can cause engine performance problems. When they do fail, the vehicle will usually produce a few symptoms that can notify the driver that there may be a problem that should be serviced.
Poor engine performance, sluggish acceleration, and lack of power
A symptom commonly associated with a problematic barometric pressure sensor is a poorly performing engine. If the BAP sensor malfunctions, it can send an incorrect signal to the computer which may have a negative effect on engine performance. The reading from the BAP sensor helps to determine fuel and timing conditions, so if the signal is compromised for any reason, then the computer calculations will be thrown off. This may result in sluggish acceleration, lack of power, and misfires in more severe cases.
Check Engine Light comes on
Another common symptom of a failed BAP sensor is an illuminated Check Engine Light. If the computer picks up on a problem with the BAP sensor or signal, it will illuminate the Check Engine Light to alert the driver that an issue has been detected.
BAP sensors are important components found on many modern engine management systems. While they are simple in nature because they operate using atmospheric pressure, they can be difficult to test. For this reason, if you suspect that your BAP sensor may be having a problem, or your Check Engine Light has come on, have the vehicle inspected by a professional technician, such as one from YourMechanic. They will be able to determine if your car needs a barometric sensor replacement, or make any other repairs that are appropriate.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Barometric Sensor and was authored by Ed Ruelas.