Filter
Top Products
FUEL SYSTEM (DFI) 3-53
Atmospheric Pressure Sensor (Service Code 15)
Output Voltage Inspection
•
Measure the output voltage at the ECU in the sam e way
as input voltage inspection. Note the following.
Digital Meter [A]
ECU Connector [B]
Atmospheric Pressure S ensor Output Voltage
Connections to ECU
Meter (+) → G/W lead (terminal 4)
Meter (–) → BR/BK lead (terminal 14)
Usable Range:
3.74 ∼ 4.26 V DC at the standard
atmospheric pressure (101.32 kPa,
76 cmHg abs.)
NOTE
○
The output voltage changes according to the local at-
mospheric pressure.
•
Turn the ignition switch OFF.
If the output voltage is within the usable range, check the
ECU f or its ground, and power supply (see this chapter).
If the output voltage is out of the standard, remove the
seat cover and check the wiring. And if the output voltage
is 4.8 V, the EC U is normal.
If the wiring is good, check the sensor for various vacuum.
If the output voltage for various vacuum is normal, check
the ECU for its ground, and power supply ( see ECU sec-
tion).
○
Determine the local altitude (elevation).
If you know the local atmospheric pressure using a
barometer, substitute the atmospheric pressure for Pv
(throttle vacuum) in the vacuum sensor chart (see inlet
air pressure sensor section in this chapter).
○
Get the usable range of the atmospheric pressure sensor
output voltage in the same way as Output Voltage Inspec-
tion of the inlet air pressure sensor and check if Va (output
voltage) is within the usable range or not.
If you know the local altitude, use the following chart.
For example:
Suppose the local altitude is 1 300 m (4 265 ft) and the
sensor output voltage Va is 3.3 V.
Plot this H (1 300 m, 4 265 ft) at a point [1] on the fol-
lowing chart and draw a vertical line through the point.
Then, you can get the usable range [2] of the sensor out-
put voltage.
Usable Range = 3.2 ∼ 3.64 V
Plot Va (3.3 V) on the vertical line → Point [3]
Results: In the chart, Va is within the usable range
and the sensor is normal.