Polaris 2012 Sportsman Forest 500 International, Service Manual

Page: 169 / 432

4.54
500 EFI FUEL SYSTEM
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
ENGINE TEMPERATURE SENSOR
General Information
Mounted on the cylinder, 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 it's 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. If for any reason the engine temperature sensor
circuit is interrupted, the fan will default to “ON”.
Engine Temperature Sensor Test
Polaris dealers can test the sensor by using the Polaris
Digital Wrench
Ô
Software (dealer only). Refer to the
Digital Wrench
Ô
Software Manual for more information.
To measure the sensor using an ohmmeter, place the
tester leads on each terminal an read the resistance with
the sensor at an ambient temperature of 68
°
F (20
°
C).
Engine Temperature Sensor Replacement
1. Disconnect sensor from engine harness.
2. Using a wrench, remove and replace the sensor,
applying a light coating of thread sealant to aid
installation.
3. Torque the sensor to specification.
Engine Coolant Temperature Sensor (ECT)
Table 4-2: Resistance Readings
T
EMPERATURE

F (

C)
R
ESISTANCE
68

F (20

C) 37.3 - 39.2 k

= T
ETS Installation Torque:
18.5 ft. lbs. (25 Nm)