Engine Coolant Temperature Sensor (Ect); Operation Overview; Ect Sensor Test; Ect Sensor Replacement - Polaris Sportsman 850 Service Manual

ENGINE COOLANT TEMPERATURE SENSOR (ECT)

OPERATION OVERVIEW

The engine coolant 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 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
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 4 for additional ECT information. Polaris
dealers can test the sensor by using the Digital Wrench®
Diagnostic Software (dealer only).
TEMPERATURE °F (°C)
32 °F (0 °C)
68 °F (20 °C)
176 °F (80 °C)
212 °F (100 °C)

ECT SENSOR REPLACEMENT

1. Remove the seat and both LH side panels.
2. Drain coolant to level below the ECT sensor.
3. Disconnect the wire harness from the ECT sensor.
4. Remove the clamp
RESISTANCE
5. Remove and replace the sensor, applying a light
5.9kΩ ± 5%
6. Torque the ECT sensor to specification.
2.5kΩ ± 5%
323Ω ± 5%
186Ω ± 5%
7. Reverse the previous steps to assemble the vehicle.
q
from the coolant bypass hose,
then pull the hose from the bottom of the thermostat
housing to allow enough access for ECT sensor
removal.
coating of thread sealant to aid installation.
TORQUE
ECT Sensor:
17 ft. lbs (23 Nm)
FUEL SYSTEM
w
4
4.35