Manifold Pressure/Vacuum Sensor: Testing and Inspection

A Tech 1 scan tool displays manifold pressure in volts. Low pressure (high vacuum) reads a low voltage while a high pressure (low vacuum) reads a high voltage. A failure in the Manifold Absolute Pressure (MAP) sensor circuit should set a DTC 33 or 34 and using the chart will find the cause of the problem. A DTC 33 may be set if a rough or unstable idle exists. Chart C-1D can also be used to check MAP sensor.