Crankshaft Balance Interrupter Ring

WARNING: This page is about a different car, the 2004 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Each interrupter ring has blades and windows that either block the magnetic field or allow it to close one of the hall-effect switches. The outer hall-effect switch sends a pulse called the 18X reference signal. The outer interrupter ring has 18 evenly spaced blades and windows. The 18X reference signal produces 18 ON-OFF pulses per crankshaft revolution. The inner hall-effect switch sends a pulse called the sync signal. The inner interrupter ring has 3 unevenly spaced blades and windows of different widths. The sync signal produces 3 different length ON-OFF pulses per crankshaft revolution. When the sync interrupter ring window is between the magnet and the inner switch, the magnetic field will cause the sync hall-effect switch to ground the supplied voltage from the ICM. The 18X interrupter ring and the hall-effect switch react similarly.