Manifold Absolute Pressure (Map) Sensor
The MAP sensor is located near center of firewall. MAP Sensor receives manifold pressure information through vacuum hose from throttle body. See Fig 1 . The MAP sensor reacts to absolute pressure in the intake manifold and provides an input voltage to the ECU. As engine load changes, manifold pressure varies, causing MAP sensor resistance to change. This change in MAP sensor resistance results in a different input voltage to the ECU. The input voltage level supplies ECU with information relating to ambient barometric pressure during engine start-up (cranking) and to engine load when engine is running. ECU computes this information and adjusts air/fuel mixture accordingly.