Powertrain Controls - ECM/PCM

Diagnostic Chart:

Manifold Absolute Pressure Sensor Wiring.:

MAP Sensor Operational Chart.:

DESCRIPTION

The manifold absolute pressure (MAP) sensor is a variable resist or that responds to changes in manifold pressure (vacuum). The PCM measures the voltage drop across the MAP sensor. The voltage ranges from 1.0 to 1.5 volts at idle (high vacuum) to 44.5 volts at wide open throttle (low vacuum).

CODE PARAMETERS

Code 33 will set if:

^ MAP is greater than 4.2 volts

^ TPS is less than 5 percent.

^ Code 21 and 22 are not present.

DIAGNOSTIC AIDS

When attempting to diagnose an intermittent problem use the Scan Tool to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem. Select MALF History from Scan Tool EC menu.

^ Check the tightness of the female terminal grip with a spare male terminal.

^ With engine Off and key On the map reading should be the same as barometric because manifold pressure is equal to atmospheric pressure (no vacuum - high voltage). Comparing this reading to a known good vehicle with the same sensor is a good way to verify accuracy of a suspect sensor. Readings should be within 0.4 volts.