Service manual

Table Of Contents
3-48 FUEL SYSTEM (DFI)
Inlet Ai r Pressure Sensor (Service Code 12)
Suppose:
Pg: Vacuum Pressure (gauge) to Sensor
Pl: Local Atmospheric Pressure (absolute) measured by a barometer
Pv: Vacuum Pressure (absolute) to Sensor
Vv: Sensor Output Voltage (V)
then
Pv = Pl Pg
For example, suppose the following data is obtained:
Pg = 8 cmHg (Vacuum gauge reading)
Pl = 70 cmHg (Varometer reading)
Vv = 3.2 V (Digital meter reading)
then
Pv=70–8=62cmHg(Abs.)
Plot this Pv (62 cmHg) at a point [1] on the chart and draw a vertical line through the point. Then, you
can get the usable range [2] of the sensor output voltage.
Usable range = 3.04 3.49 V
Plot Vv (3.2 V) on the vertical line. Point [3].
Results: In the chart, Vv is within the usable range and the sensor is normal.