Service manual

Fuel Injection System 7
71
11-3 Temperature sensor
Function:
The sensor is used to provide information about water coolant,
cylinder temperature, or intake temperature.
Principle:
As one NTC (Negative Temperature Coefficient) thermistor, the temperature sensor has its resistance
descending with the water coolant’s ascendant temperatures in which there is no linear relationship.
Fault diagnosis:
Any error signal for the temperature of water coolant or the cylinder higher than the upper limit will be
indicated on the dashboard. However, the temperature of the water coolant or the cylinder less than the lower
limit may not be attributed to a defective temperature sensor but the engine just started or warm-up. In the event
of any error signal still indicated on the dashboard with the possible trouble excluded, please test the
component.
Method of measurement: Dip the temperature sensor inside hot water at 80℃ first; take out the sensor and
measure resistance. If normal, please check other circuits of the engine temperature sensor.
Measured data:
Temperature Resistance
-10℃ 10．28 k

+20℃ 2．5 k

±5%
+80℃ 0．345 k

Range of temperatures -30℃~+130℃
Temperature sensor
Sectional view of a temperature
sensor:
1. Electric connector; 2. Bushing; 3.
NTC thermistor.