4-14
3. Remove the two torx-head screws securing the ECU
to the mounting bracket.
Installing (F/M/XF 1100 cc)
1. Secure the ECU to mounting bracket using the exist-
ing two torx-head screws. Tighten securely.
2. Install the ECU with mounting bracket onto the rear
belt guard until it snaps into place.
3. Connect the two wiring connectors to the ECU.
4. Secure the lower console using the retaining ring;
then install the left-side access panel.
NOTE: Make sure all connectors are clean and tight.
Apply dielectric grease to all connector seals.
AIR TEMPERATURE SENSOR
This sensor detects air temperature entering the air
silencer and engine. The ECU sends current to this sensor,
and (depending on the temperature) the sensor will pass a
certain amount of current through the sensor to ground.
The ECU measures how much current passes through the
sensor to ground. From this measurement, the ECU deter-
mines the air temperature and calculates the fuel/air mix-
ture ratio. Resistance will drop as the temperature rises.
Removing
1. Disconnect the wiring harness from the air tempera-
ture sensor.
2. Using a flat-blade screwdriver, pry the sensor end to
end to remove it from the air silencer. Account for
two push pins.
Installing
1. Place the sensor into position in the air silencer and
secure with push pins.
2. Connect the wiring harness to the air temperature
sensor. Secure the sensor wires with cable ties so
they do not rub on any other components.
COOLANT TEMPERATURE SENSOR
This sensor detects coolant temperature. The ECU measures
the current flow through the sensor to ground. From this mea-
surement, the ECU can determine the engine coolant temper-
ature and calculate the correct fuel/air mixture ratio.
NOTE: If the coolant temperature rises above 75° C
(167° F) (2-Stroke), the temperature sensor starts to
richen the fuel mixture. At this time, the check engine
light will flash constantly. Once the engine coolant tem-
perature reaches the specified temperature 90° C (194°
F), the temperature sensor will signal the ECU to go into
the rich mode to protect the engine while overheating. At
this time, the check engine light will be constantly on.
NOTE: If the coolant temp rises above 105°C (221° F) (4-
Stroke) the temp light on the gauge will start to flash and
the engine will go into a fuel cut (surging) mode to alert
the rider of overheating. If the temp continues to rise and
exceeds 110°C (230° F) the temp light will be on continu-
ously. The fuel cut will not protect the engine from over-
heating if the operator continues to ride the snowmobile.
THROTTLE POSITION SENSOR
This sensor is a potentiometer (essentially, a resistor).
This sensor transforms the throttle-valve position into
output voltage to the ECU. In addition, the sensor detects
the opening or closing speed of the throttle valve and
feeds that rate of voltage change to the ECU.
NOTE: The input from the throttle position sensor is
one of the main inputs for the ECU calculation of fuel/
air mixture ratio.
IGNITION TIMING SENSOR
This sensor is triggered by teeth precisely mounted to the
flywheel flange. Each time a tooth rotates past the sensor,
a signal is sent to the ECU. From this signal, the ECU
determines ignition and injection timing and RPM.
BAROMETRIC PRESSURE SENSOR
This sensor is part of the ECU. Its purpose is to sense
atmospheric pressure. From this information, the ECU
determines the correct fuel/air mixture ratio.
NOTE: On 2-stroke models, the sensor is not
replaceable. If it should fail, the ECU must be
replaced.
FUEL INJECTORS
A fuel injector is an electromagnetic injection valve con-
trolled by a signal from the ECU. The coil used in the
injector is a high-pressure resistance type. The ECU
determines the optimum fuel injection time and duration
based on signals from the sensors.
When voltage is sent to the fuel injector, it energizes the
coil and opens the needle valve, thereby injecting fuel.
Because the fuel pressure (pressure differential between
fuel line and manifold) is kept constant, the amount of
fuel injected is determined by the duration of time the
valve is open and manifold pressure.
On the 500 cc, the injectors are coded with letters (A-B-
C). On the 800 cc, the injectors are coded with symbols
(
-
-
) and are color-coded yellow and green. When
replacement of a fuel injector is necessary, the injector
must be replaced with an injector of the same code sym-
bol/letter and color.
IO031A
CAUTION
Do not replace an injector with one of a different code
symbol or letter. Severe engine damage may occur.
500 cc
Summary of Contents for Sno Pro 120
Page 20: ...1 18 NOTES ...
Page 29: ...2 9 2 570ENG12 ...
Page 39: ...2 19 2 500CC2A_12 ...
Page 45: ...2 25 2 NOTES ...
Page 47: ...2 27 2 800_12_2 ...
Page 61: ...2 41 2 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 63: ...2 43 2 1100ccZ1RV10 ...
Page 81: ...2 61 2 1100ccZ1RV10 ...
Page 82: ...2 62 Engine Torque Patterns 1100 cc 1100TorquePattern12 ...
Page 141: ...2 121 2 SNO2152 ...
Page 142: ...2 122 SNO2153 ...
Page 180: ...3 18 0742 314 0746 520 F5 LXR 800 cc ...
Page 204: ...3 42 NOTES ...
Page 260: ...5 26 Troubleshooting Servomotor SERVO1A12 ...
Page 261: ...5 5 27 SERVO2rv ...
Page 264: ...Magneto 0746 255 1 ...
Page 266: ...Main Harness p n 1686 603 F5 LXR 0746 249 3 ...
Page 269: ...Main Harness p n 1686 588 F 800 M 800 XF 800 0746 242 6 ...
Page 270: ...Main Harness p n 1686 611 TZ1 Turbo LXR LTD 0746 253 7 ...
Page 271: ...Main Harness p n 1686 610 TZ1 TZ1 LXR 0746 252 8 ...
Page 272: ...Main Harness p n 1686 613 Bearcat Z1 XT GS p n 1686 615 Bearcat Z1 XT LTD 0746 511 9 ...
Page 273: ...Main Harness p n 1686 578 Sno Pro 120 10 0744 204 ...
Page 274: ...Ignition Main Harness p n 1686 628 Sno Pro 500 11 0745 605 ...
Page 275: ...Ignition Main Harness p n 1686 657 Sno Pro 600 12 0746 250 ...
Page 276: ...0745 601 13 Console Harness p n 1686 631 TZ1 LXR TZ1 Turbo LXR LTD ...
Page 277: ...Hood Harness p n 1686 638 F 800 M 800 XF 800 0746 243 14 ...
Page 278: ...Console Harness p n 1686 633 Bearcat 570 F570 T570 0746 238 15 ...
Page 279: ...Console Harness p n 1686 634 F5 LXR 0746 240 16 ...
Page 280: ...Hood Harness p n 1686 639 F 1100 Turbo M 1100 Turbo HCR XF 1100 Turbo 0746 246 17 ...
Page 282: ...0746 254 19 Console Harness p n 1686 547 Bearcat Z1 XT GS p n 1686 549 Bearcat Z1 XT LTD TZ1 ...
Page 283: ...Hood Harness p n 1686 587 Sno Pro 500 20 0744 201 ...
Page 285: ...Passenger Seat Harness p n 1686 570 22 0744 197 ...
Page 286: ...Handlebar Harness p n 1686 636 F 800 M 800 XF 800 p n 1686 654 M 800 HCR 0746 244 23 ...
Page 287: ...Handlebar Harness p n 1686 537 Bearcat 570 F570 T570 0746 239 24 ...
Page 288: ...Handlebar Harness p n 1686 574 F5 LXR 0744 189 25 ...
Page 289: ...Handlebar Harness p n 1686 637 F 1100 Turbo M 1100 Turbo XF 1100 Turbo 0746 247 26 ...
Page 290: ...Handlebar Harness p n 1686 590 Sno Pro 500 27 0744 200 ...
Page 291: ...Handlebar Harness p n 1686 656 M 1100 Turbo Sno Pro HCR 28 0746 510 ...
Page 292: ...Misc Groomer Special p n 1686 645 p n 1686 646 p n 1686 647 p n 1686 648 29 0746 241 ...
Page 460: ...8 26 0744 930 ...