Manifold Absolute Pressure (Map) Sensor

The MAP sensor measures changes in manifold pressure. Changes in manifold pressure result from engine load and speed changes. The MAP sensor converts these changes in manifold pressure into a voltage output signal to ECM (1.5 volts at idle to 4.5 volts at WOT). The ECM can monitor these signals and adjust air/fuel ratio and ignition timing under various operating conditions. If MAP sensor fails, the ECM will substitute a fixed MAP value and will use the TPS to control fuel delivery. A fault in the MAP circuit should set a Code 33 or 34. If Code 33 or 34 is not present and MAP sensor is suspected of causing a driveability problem, see appropriate CHART C1D for that system.