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9924880 Rev 2- 1/10/2014 - 2013 / 2014 RANGER XP 900 - 2014 RANGER XP 900 / CREW 900 Service Manual
© Copyright Polaris Sales Inc.
4.27
ENGINE COOLANT TEMPERATURE SENSOR (ECT)
OPERATION OVERVIEW
Mounted in the cylinder head, the engine temperature
sensor measures coolant temperature. The engine
temperature sensor is a Negative Temperature
Coefficient (NTC) type sensor, as the temperature
increases the resistance decreases.
Coolant passes through the cylinder head and by the
sensor probe, varying a resistance reading which is
relayed to the ECU. This signal is processed by the ECU
and compared to its programming for determining the
fuel and ignition requirements during operation. The ECU
also uses this signal to determine when to activate the
cooling fan during operation.
ECT SENSOR TEST
To quickly rule out other components and wiring related
to the ECT, disconnect the harness from the ECT sensor
and start the engine. After a few seconds, the fan should
turn on and the “Check Engine” indicator should display
on the instrument cluster. This indicates all other
components are working properly.
Refer to Chapter 10 for additional ECT sensor
information. Polaris dealers can test the sensor by using
Digital Wrench® Diagnostic Software (dealer only).
ECT Sensor Resistance Readings
TEMPERATURE °F (°C)
RESISTANCE
68 °F (20 °C)
2.5k Ω ± 6%
86 °F (30 °C)
1.7k Ω ± 6%
TEMPERATURE °F (°C)
RESISTANCE
104 °F (40 °C)
1.2k Ω ± 6%
122 °F (50 °C)
834 Ω ± 6%
140 °F (60 °C)
596 Ω ± 6%
158 °F (70 °C)
435 Ω ± 6%
176 °F (80 °C)
323 Ω ± 6%
194 °F (90 °C)
243 Ω ± 6%
212 °F (100 °C)
186 Ω ± 6%
ECT SENSOR REPLACEMENT
1. Lift the rear cargo box to the raised position.
2. Drain the coolant so the level is below the sensor
(see Chapter 2 “Coolant Drain / Fill”).
3. Remove the fuel line from fuel rail (see “Fuel Line
Removal / Installation”).
4. Disconnect the vehicle harness from the ECT sensor.
5. Using a wrench, loosen and remove ECT sensor
from engine.
6. Apply thread sealant to the new sensor threads and
install it into the cylinder head.
7. Torque the new ECT sensor to specification and
connect the vehicle harness to the sensor.
TORQUE
ECT Sensor:17 ft-lbs (23 Nm)
8. Reconnect the fuel line to the fuel rail.
9. Add the required amount of coolant and bleed the
system (see Chapter 3 “Cooling System Bleeding
Procedure”).
FUEL SYSTEM - GENERAL
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