500 EFI FUEL SYSTEM
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.
Engine Coolant Temperature Sensor (ECT)
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".
4.54
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
Engine Temperature Sensor Test
Polaris dealers can test the sensor by using the Polaris
Ô
Digital Wrench
Software (dealer only). Refer to the
Ô
Digital Wrench
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
Table 4-2: Resistance Readings
F (C)
T
EMPERATURE
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.
ETS Installation Torque:
18.5 ft. lbs. (25 Nm)
°
°
F (20
C).
R
ESISTANCE
37.3 - 39.2 k
= T