That must be a steel flywheel.
See the inner ring with two teeth missing?
Thats the trigger for the crank sensor.
Crank sensor is a hall effect sensor that measures magentic field.
When a tooth goes before the sensor it will detect the change in magnetic field and produce a waveform. From the teeth it will get a square waveform telling the ECU the RPM. From the missing tooth it will know the crank angle (hence the ECU then knows when the engine is at TDC).
So it needs a ferrous material to work the hall sensor.
See the inner ring with two teeth missing?
Thats the trigger for the crank sensor.
Crank sensor is a hall effect sensor that measures magentic field.
When a tooth goes before the sensor it will detect the change in magnetic field and produce a waveform. From the teeth it will get a square waveform telling the ECU the RPM. From the missing tooth it will know the crank angle (hence the ECU then knows when the engine is at TDC).
So it needs a ferrous material to work the hall sensor.