Chery A21 2005, Service Manual, Page: 337 / 475

CHERY
·
A21 SERVICE MANUAL ENGINE EFI SYSTEM
14
3.2 COOLANT TEMPERATURE SENSOR
1)exterior drawing and pin
This sensor has two exchangeable pins.
2)Purpose: The sensor provide the coolant
temperature signal to ECU for ignition timing
and modifying fuel injection of starting, idle
speed and normal working.
3)Installation position
Coolant temperature sensor was installed on the
water outlet of cylinder block and the copper
heat conducted socket was inserted into water.
There are thread on the socket, and screw in
coolant temperature sensor onto the threaded
hole on cylinder block by the hexagon head of
the socket. The maximum moment is 20Nm.
4)Working principle
This sensor is a thermistor of negative
temperature coefficient (NTC), and its value
will decrease with the coolant temperature
increasing but the changes are not linearity.
There are several different resistance values at
different temperature:
T(
℃
) Resistance value(k
Ω
)
-10 8.62----10.28
20 2.37----2.63
80 0.299----0.345
5)Normal working temperature: -30----130
℃
Normal working voltage: 5V DC
6)Malfunction phenomenon and diagnosis
method
l
Malfunction phenomenon : Difficult to
start.
l
Reasons of malfunction: man made
l
Simple measurement method:
Chart 3-2 Outlook drawing of the
coolant temperature sensor
Chart 3-3 Circuit diagram of coolant
temperature sensor
Coolant Temperature Sensor
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