No Change In MAP From Start to Run

WHEN MONITORED
With engine speed between 400 and 1500 RPM, and the throttle closed.

SET CONDITION
Too small a difference is seen between barometric pressure at ignition on and manifold vacuum (engine running) for 1.72 seconds.

THEORY OF OPERATION
This sensor provides a 0 to 5 volt signal to PCM cavity 1, which represents Manifold Absolute Pressure (MAP), (while the engine is running), and ambient barometric pressure (when the engine is OFF).

- Low voltage output signal (0.5 to 1.8 volts) at idle, (when manifold vacuum is high).

- High voltage output signal (3.9 to 4.8 volts), at deep throttle (when manifold vacuum is low).

The MAP sensor receives a 4.8 to 5.1 volt supply from PCM cavity 6, and a sensor ground from PCM cavity 4.

PROBABLE CAUSES
- Restricted or leaking vacuum/pressure to MAP sensor
- Ice in sensor or passage
- Failed sensor
- Failed PCM