Symptoms

- Engine Light ON (or Service Engine Soon Warning Light) - Engine rough idle - Engine hesitation

Possible Causes

- Barometric Pressure harness is open or shorted - Barometric Pressure sensor poor electrical circuit connector - Faulty Barometric Pressure sensor - Faulty Powertrain Control Module (PCM) or Engine Control Module (ECM)

When Detected

An excessively low or high voltage from the sensor is sent to ECM.

Description

The Barometric Pressure (MAP) sensor provides instantaneous manifold pressure information to the engine's Engine Control Module (ECM). The data is used to calculate air density and determine the engine's air mass flow rate, which in turn determines the required fuel metering for optimum combustion. A fuel-injected engine may alternately use a Mass Air Flow (MAF) sensor to detect the intake airflow. A typical configuration employs one or the other, but seldom both.