4.35
ELECTRONIC FUEL INJECTION
4
9924125 - 2013 RANGER RZR / RZR S / RZR 4 Service Manual
© Copyright 2012 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
p
robe, 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 3 and 10 for additional ECT sensor
i
nformation. Polaris dealers can test the sensor by using
the Digital Wrench™ Diagnostic Software (dealer only).
ECT Sensor Replacement
1. Remove the driver and passenger seats.
2. Remove the rear service panel to access the ECT
se
nsor.
3. Drain coolant to level below
sensor.
4. Disconnect sensor from engine harness.
5. Using a wrench, remove and replace the sensor,
a
pplying a light coating of thread sealant to aid
installation.
6. Torque the sensor to specification.
7. Add the required amount of coolant and properly
b
leed the cooling system (see Chapter 3).
ECT Sensor Resistance Readings
Temperature F (C) Resistance
68 F (2
0 C) 2.5k ± 6%
86 F (3
0 C) 1.7k ± 6%
104 F (4
0 C) 1.2k ± 6%
122 F (5
0 C) 834 ± 6%
140 F (6
0 C) 596 ± 6%
158 F (7
0 C) 435 ± 6%
176 F (8
0 C) 323 ± 6%
194 F (9
0 C) 243 ± 6%
212 F (1
00 C) 186 ± 6%
ECT Sensor:
17 ft-lbs (23 Nm)
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