54
LAUNCH
X-431 PAD V
User's Manual
from the left.
[ ]: Reduces the range and zoom in the waveform.
[ ]: Increase the range and zoom out the waveform.
[ ]: Starts or stops the testing process.
7.1.4.2 Test sample
Knock sensor testing
(1) Resistance test for knock sensor
Switch ignition “OFF”, unplug the wire connector of knock sensor, test
the resistance between the wire terminal and the case of knock sensor
with “Resistance test” function, it shall be ∞(disconnected), and if it
is 0Ω(conductive), which means the knock sensor shall be replaced.
For the magnetostriction knock sensor, it can also test the resistance
by the “Resistance measurement” function; the resistance shall be
compliant with the specified value (see specific service manual for the
detailed data), otherwise, the knock sensor shall be replaced.
(2) Checking for the output signal of knock sensor
Unplug the wire connector of knock sensor, check voltage between
knock sensor connector terminal and ground wire of knock, it should
be output pulse 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 1kΩ 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.
