The manifold absolute pressure (MAP) sensor is a device that is mounted to the intake manifold of your engine. This device reads the pressure inside the intake manifold and sends the resulting data to the engine control module (ECM). The ECM then uses the data to calculate the proper amount of fuel to inject into the cylinders in order to maintain the optimum air/fuel ratio and keep your engine running smoothly. In addition, other engine functions are controlled or calculated with input from the MAP sensor, such as the amount of exhaust gas that might be produced. This device works in tandem with the mass airflow sensor to adjust engine operation in response to changing conditions.
For every cubic foot of air that is drawn into the intake manifold of your engine, the combustion process requires that a specific amount of fuel be added at the same time. Data from the MAP sensor is one of the ways in which the ECM accomplishes the task. If the ECM receives bad data, or no data at all, from the MAP sensor, then the air/fuel mixture entering the cylinders will be wrong. If that mixture is incorrect, the following symptoms can occur:
To replace the MAP (manifold absolute pressure) sensor, a technician will likely perform the following measures:
