Yamaha UMAX, Service Manual

Page: 263 / 320

ELECTRICAL COMPONENTS (YUM1A/YUM2A)
8-58
b. Connect the digital circuit tester to the test
harness S– pressure sensor 5S7 (3P).
c. Turn the main switch to “ON”.
d. Measure the intake air pressure sensor
output voltage.
CHECKING THE INTAKE AIR
TEMPERATURE SENSOR
1. Remove:
• Intake air temperature sensor
(from the air filter case.)
WARNING
• Handle the intake air temperature sensor
with special care.
• Never subject the intake air temperature
sensor to strong shocks. If the intake air
temperature sensor is dropped, replace it.
2. Check:
• Intake air temperature sensor resistance
Out of specification
→
Replace.
a. Connect the digital circuit tester to the in-
take air temperature sensor terminals as
shown.
b. Immerse the intake air temperature sen-
sor “1” in a container filled with water “2”.
TIP
Make sure that the intake air temperature sensor
terminals do not get wet.
c. Place a thermometer “3” in the water.
d. Heat the water or let it cool down to the
specified temperatures.
e. Measure the intake air temperature sen-
sor resistance.
CHECKING THE FUEL INJECTOR
1. Check:
• Fuel injector resistance
Out of specification
→
Replace the fuel injec-
tor.
a. Disconnect the fuel injector coupler from
wire harness.
b. Connect the digital circuit tester to the fuel
injector terminals as shown.
Test harness S– pressure sensor
5S7 (3P)
90890-03207
Test harness S– pressure sensor
5S7 (3P)
YU-03207
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with ta-
chometer
YU-A1927
• Positive tester probe
→
green (wire harness color)
• Negative tester probe
→
black/white (wire harness color)
1
Intake air temperature sensor re-
sistance
2.21–2.69 k
Ω
at 20 °C
(2.21–2.69 k
Ω
at 68 °F)
Intake air temperature sensor re-
sistance (reference data)
0.322 k
Ω
at 80 °C
(0.322 k
Ω
at 176 °F)
Digital circuit tester (CD732)
90890-03243
Model 88 Multimeter with ta-
chometer
YU-A1927
Resistance
12.0
Ω
3
1
2