Knock sensor: what is the normal output voltage?

Hello everybody,

Thanks to "Theta00" (a user of this newsgroup), i located my knock sensor on
my Hyundai Scoupe '93. It was a diagnostic code reporting a trouble relative
to this component.
In order to see if it is really the device that is faulty, rather than a
loose/bad connection somewhere in this circuit, i connected an oscilloscope
on this device, which should be a piezoelectric component, to see what can
be his output voltage, while the engine is running. I read only 0.4 Volt
peak to peak, which i supposed to be non-normal voltage on this sensor,
piezoelectric devices delivering normally a greatest amplitude voltage. This
voltage appeared pratically immerged in the environmental noise of the
motor.

My question is: Is it a normal voltage for such a device?
If no, i'll know i have to replace it.

Thank you very much!

 

the info on the knock sensor is available on the hyundai usa web site.
the normal resistance for it is 5 mega ohms.
the voltage should be less than .605v
your's may be still OK. but that doesn't help.



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