Yamaha WaveRunner VXR VX1800A, Service Manual

Page: 224 / 318

7-17
Control system
2. Supply power to the ECM, and then mea-
sure the input voltage at the engine tem-
perature sensor coupler terminals (wire
harness end). Check the wire harness if
out of specification.
3. Remove the engine temperature sensor.
See “Cylinder block and electrical part”
(5-67).
4. Suspend the engine temperature sensor in
a container filled with water, and then heat
the water slowly.
5. Measure the engine temperature sensor
resistance when the specified tempera-
tures are reached. Replace if out specifica-
tion.
6. Install the engine temperature sensor. See
“Cylinder block and electrical part” (5-67).
7. Connect the engine temperature sensor
coupler.
Intake air temperature sensor check
1. Measure the ambient temperature.
2. Connect the YDIS to display “Intake tem-
perature”.
3. If the ambient temperature and the dis-
played intake air temperature differ by
more than ± 5 °C (± 9 °F), measure the in-
take air temperature sensor resistance.
TIP:
Check the intake air temperature sensor when
the engine is cold.
4. Disconnect the intake air temperature sen-
sor coupler “a”.
5. Supply power to the ECM, and then mea-
sure the input voltage at the intake air tem-
perature sensor coupler (wire harness
end). Check the wire harness if out of
specification.
6. Remove the intake air temperature sen-
sor. See “Intake manifold” (5-24).
7. Suspend the intake air temperature sensor
in a container filled with water, and then
slowly heat the water.
Input voltage
4.75–5.25 V
Black/Yellow (B/Y)–Black/Orange (B/O)
Resistance at 20°C (68°F)
54.2–69.0 k
Ω
Resistance at 100°C (212°F)
3.12–3.48 k
Ω
a
B/Y B/O
B/Y B/Y
Input voltage
4.75–5.25 V
Black/Red (B/R)–Black/Orange (B/O)
B/R B/O
a