Example: Camshaft Sensor
(Hall effect) Waveform

Automotive waveforms

Camshaft Sensor (Hall Effect) Waveform Notes

The camshaft sensor is sometimes referred to as the Cylinder Identification (CID) sensor and is used as a reference to time the sequential fuel injection. The signal waveform can be either a permanent magnetic sine wave or in this particular case a digital square wave.
The Electronic Control Module (ECM) needs to see the signal when the engine is started for its reference; if absent, it can put the ECM into 'limp-home'.

The characteristics of a good Hall effect waveform is clean, sharp switching and as with all other Hall units has 3 electrical connections.


Fig. 101.1

Figure 101.1 shows the camshaft sensor in situ. The rotor disc on the camshaft pulley can clear be seen with the four cut outs that generate the waveform above.