Atmospheric Pressure Sensor
The atmospheric pressure sensor supplies the engine control module (ECM) with a signal describing air pressure. It provides the engine control module (ECM) with the car's height above sea level.
Atmospheric pressure sensor acts on the control of:
- boost pressure at high altitude
- injection time when starting at high altitude.
At heights above 2400 meters the following are disabled:
- leak diagnostic
- pulsed secondary air injection (PAIR) diagnostic
- mass air flow (MAF) sensor, faulty signal.
The atmospheric pressure sensor contains a piezo-electric crystal in the shape of a diaphragm. One side of this diaphragm is subject to atmospheric pressure, to other side is acted on by a contained gas. The deformation of the piezo-electric diaphragm, and therefore its resistance is proportional to air pressure.
The voltage across the sensor is a function of air pressure and, therefore, of sensor resistance.
Voltage can vary between 0 V and 5 V.
The sensor is supplied with a stabilized voltage of 5 V from the engine control module (ECM).
If the signal from the atmospheric pressure sensor is faulty or missing the engine control module (ECM) adopts a substitute value.
The atmospheric pressure sensor is located by the right hood catch.