VSS - Vehicle Speed Sensor - 2 wire Hall type

Ecu Hardware Modifications
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VSS - Vehicle Speed Sensor - 2 wire Hall type

Postby BennVenn » Sat Sep 04, 2021 12:36 pm

I can't seem to find this information anywhere so I'm posting it here for preservation sake.

The ABS / Wheel speed sensor in a VE commodore and pretty much all late model cars is a two pin sensor. It is not Variable Reluctance (VR) as it was pre-VE, rather a device which will either flow 7mA or 14mA of current depending if it is on a tooth or a gap.

An equivalent circuit is below:

VE_Hall.PNG (5.95 KiB) Viewed 125 times

The diode is helpful as you can check the correct polarity of the sensor with a multimeter.

Using a 220 ohm resistor in series with the sensor, with 12v applied you can expect to see 1.55volts or 3.2volts across the 220R resistor depending on a tooth/gap. A simple comparator can convert this to digital logic level for an ECU/MCU.

You could also check for 0.6v across the sensor which would indicate the sensor is wired backwards, 12v on the resistor if the sensor is shorted or 0v if the sensor is open circuit (This error detection is why manufactures have switched to this type of sensor)

These sensors are available on eBay for $20 a pair, very cheap for an automotive grade hall sensor, could be used for crank/cam tooth sensing and will sense from zero RPM.

I hope someone else finds this info helpful!

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