Knock sensor: what is the normal output voltage?

[Rollon]

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!

 

[Jim Vatunz]

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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