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3-44 FUEL SYSTEM (DFI)
Inlet Air Pressure Sensor (Service Code 12)
Output Voltage Inspection
NOTE
○
The output voltage changes according t o the local at-
mospheric pressure.
•
Measure the output voltage at the ECU in the same way
as input voltage inspection. Note the following.
Inlet Air Pressure Sensor O u tput Voltage
Connections to ECU
Meter (+) → Y/BL lead (terminal 17)
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.)
•
Turn the ignition switch OFF.
If the output voltage is within the usable range, check the
ECU for its ground, and power supply (see this chapter).
If the output voltage is out of the usable range, rem ove
the fuel tank and check the wiring. If the output voltage is
4.8 V, t he ECU 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).
•
Remove the inlet air pressure sensor [A] and disconnect
the vacuum hose from the sensor.
○
Do not disconnect the sensor connector.
•
Connect an auxiliary hose [B] to the inlet air pressure sen-
sor.
•
Temporarily install the inlet air pressure sensor.
○
Connect a comm ercially available digital meter [C], vac-
uum gauge [D], the fork oil level gauge [E] and the har-
ness adapter to the inlet air pressure sensor.
Special Tools - Fork Oil Level Gauge: 57001–1290
Sensor Harness Adapter: 57001–1561
Inlet Air Pressure Sensor Output Voltage
Connection to Adapter
Meter (+) → BL (sensor Y/BL) lead
Meter (–) → Y/W (sensor BR/BK) lead
○
TurntheignitionswitchON.
○
Measure t he inlet air pressure sensor output voltage from various vacuum readings, while pulling
the handle of the fork oil level gauge.
○
Check the inlet air pressure sensor output voltage, using the following formula and chart.
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)