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9924871 R03 - 2014 Polaris Sportsman® 570 EFI Service Manual
© Copyright 2013 Polaris Sales Inc.
ENGINE COOLANT TEMPERATURE SENSOR (ECT)
Operation Overview
Mounted on 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 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 10 for additional ECT sensor
information. Polaris dealers can test the sensor by using
the Digital Wrench Diagnostic Software (dealer only).
ECT Sensor Resistance Readings
TEMPERATURE °F (°C)
RESISTANCE
68 °F (20 °C)
2.5 kΩ ± 6%
86 °F (30 °C)
1.7 kΩ ± 6%
104 °F (40 °C)
1.2 kΩ ± 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%
FUEL SYSTEM - GENERAL
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