Phoenix Pro User Manual
90
voltage; otherwise, the knock sensor shall be replaced.
Coolant temperature sensor testing
(1) Resistance test for coolant temperature sensor
On vehicle testing:
Switch ignition “OFF” and unplug the wire connector of coolant temperature
sensor, then use the “Resistance measurement” to test the Resistance between
two terminals of sensor. The relationship between the resistance and the
temperature is in inversely proportion (negative temperature coefficient), which
shall be less than 1k
Ω
during warming up.
Independent testing:
Unplug the wire connector of coolant temperature sensor, then remove the
sensor from the engine; place the sensor into a breaker with water and heat the
water, then use the “Resistance measurement” to test the Resistance between
two terminals of coolant temperature sensor at different water temperature.
Compared the measured value with the standard value, if the Resistance is not
compliant with the standard, then the coolant temperature sensor shall be
replaced.
(2) Output signal voltage testing for coolant temperature sensor
After installing the coolant temperature sensor, plug the wire connector of
sensor, and then switch ignition ON, test the output signal voltage between the
two terminals of wire connector. The tested voltage shall be in inverse
proportional with the coolant temperature. When the harness of coolant
temperature sensor is disconnected, the voltage shall be about 5V if the ignition
switch is ON.
