No Change In MAP From Start to Run

NO CHANGE IN MAP FROM START TO RUN

When Monitored
With engine rpm above 400 but less than 1500 and the throttle body at closed throttle.

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 measures manifold absolute pressure and ambient barometric pressure within the manifold. It provides a 0 to 5-volt signal to Powertrain Control Module (PCM) cavity 1. The MAP sensor puts out a low voltage signal (0.5 to 1.8 volts) at idle when the manifold vacuum is high, and a higher voltage signal (3.9 to 4.8 volts) at deep throttle when the manifold vacuum is low. The MAP receives a 5-volt supply from PCM cavity 6; voltage may vary from 4.8 to 5.1 volts. The sensor ground is provided by PCM cavity 4.

Possible Causes
- Restricted or leaking vacuum/pressure to MAP sensor.
- Ice in sensor or passage.
- Failed sensor.
- Failed PCM.