Grand Prix V6-3.8L SC VIN 1 (1997)
evenly-spaced same-width blades and windows. The 18X crankshaft position sensor produces 18 "ON-OFF" pulses per crankshaft revolution. The
Hall-effect switch closest to the crankshaft, the 3X crankshaft position sensor, is so called because the inside interrupter ring has 3
unevenly-spaced, different-width blades and windows. The 3X crankshaft position sensor produces 3 different length "ON-OFF" pulses per
crankshaft revolution.
When a 3X interrupter ring "window" is between the magnet and inner switch, the magnetic field will cause the 3X Hall-effect switch to ground
the 3X signal voltage supplied from the ignition control module. The 18X interrupter ring and Hall-effect switch react similarly. The electronic
ignition module interprets the 18X and 3X "ON-OFF" signals as an indication of crankshaft position, and must have both signals to "fire" the
correct ignition coil.
The electronic ignition module determines crankshaft position for correct ignition coil sequencing by counting how many 18X signal transitions
occur, i.e.; "ON-OFF" OR "OFF-ON," during a 3X pulse.
