Crankshaft Sensor Description

Ignition Systems, Timing Procedures and Diagnostics 13-83


Crankshaft Sensor Description

Figure 4 - Magnetic Flux Field:

Figure 5 - Hall Effect Device Response to Vane:

The Dual Hall crankshaft sensor contains two Hall digital output devices (PIP, CID) in one package. The sensor is located on a bracket mounted near the crankshaft damper.

Two rotary vane cups (or wheels) are mounted on the damper and are used to trigger the Hall sensors. The vane cups are made of ferrous metal. When the window of a cup is in the air gap between the Hall device and the permanent magnet, a magnetic flux field is completed from the magnet through the Hall device and back to the magnet. This condition results in a low (O volt) output signal (Figure 4). As the crankshaft turns, a tooth on the cup will move into the air gap. The magnet field will be shunted by the tooth (Figure 5) preventing it from reaching the hall device and the output signal will change from a low to a high (VBAT).

The PIP cup has two teeth resulting in two positive going edges each revolution of the crankshaft, and the CID cup has one tooth and generates one positive edge each revolution of the crankshaft. CID is used by the DIS module to enable it to select the proper coil to fire. The EEC-IV processor tells the DIS module when to fire but the DIS module has to select one of the two coils based on the CID signal (which two of four coils if in the DPI mode).