does anyone know if the factory pcm uses both +positive and -negative wires from the crank sensor for refrence. or do they ground the -negative and only use the +positive for refrence?

The CS is a magnet. Power goes in on one side, magnet catches the notch, the signal doesn't come back to the ecm and there's fire.

It's the way I believe it works.

But why the question?


Gilles
2.3 Ho

The crank sensor is a magnetic pickup.
It generates an Alternating Current as ferris metal is brought near to it (+ voltage) and moved away (- voltage).
Without both wires, no current flows in either direction... aka no signal generated.

There are some instances where one side of an AC sensor is grounded in a control module (PCM) but in those cases one side of the sensor would need to be grounded to the block or chassis too, which the GM cranks sensor is not.


It may be possible to get the sensor to work somewhat with only one wire because the air can work as a huge capacitor and transmit the voltage anyway, but the signal to the pcm would be very erractic and unreliable.





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