Symptoms

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

Possible Causes

- Manifold Absolute Pressure harness is open or shorted - Manifold Absolute Pressure sensor poor electrical circuit connector - Faulty Manifold Absolute Pressure sensor - Faulty Engine Control Module (ECM)

When Detected

The Engine Control Module (ECM) has detected a performance fault with the anifold Absolute Pressure (MAP) sensor

Description

The Manifold Absolute 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.