Launch X-431 PAD III - 2. Charging system and starting system test

LAUNCH X-431 PAD III User Manual
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The following operations can be done:
[ ]: Erases the currently displayed waveform and display it starting 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.
10.2 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