Maintenance Manual for Chery·Windcloud MOTOROLA EFI System
3
3. Coolant Temperature Sensor TF-W
Purpose: this sensor is designed to provide
coolant temperature information. To provide
engine ECU with water temperature signal used
for control of ignition timing and fuel injection
pulse width in startup, idle speed and normal
operation.
Composition and principle: this sensor is a
thermistor of negative temperature coefficient
(NTC) with resistance value decreasing with
the increasing of coolant temperature and vice
versa except linear relation. ECU monitors
water temperature variation as per sensor
output signal and via comparison circuit inside.
Failure diagnosis: water temperature signal
above limit value;
Water temperature signal below limit value;
Short circuit or open circuit occurs in water
temperature sensor line.
Limiting data: 2.5±5%KΩ
Installation hint: tightening torque is 15Nm in
maximum.
Hints: the vehicle is equipped with 2 water
temperature sensors, one is single-pin water
temperature sensor, providing the water
temperature gauge with water temperature
signal; the other is double-pin, providing the
engine ECU with water temperature signal.
Coolant temperature sensor
Water temperature senso
Circuit diagram of coolant temperature sensor
Pins: this sensor has 3 pins, which can
interchange for use.
1 coolant temperature sensor signal (ECU
B10#)
2 sensor signal ground (ECU B23#)
Troubleshooting: mainly check if there is
short circuit or open circuit on the connection
between 3 lines on senosr and ECU as well as
instrument.
If there is short circuit, open circuit or
grounding between sensor wire harnesses.
Line grounding or defect grounding is liable
to cause engine water temperature gauge to
indicate excessive temperature.
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