Bonneville V6-231 3.8L VIN 3 SFI (1988)
Crankshaft Position Sensor: Description and Operation
VIN C
Crankshaft Position Sensor
DESCRIPTION
The crank sensor is mounted in a pedestal on the front of the engine near the harmonic balaner. The sensor is a "hall-effect" switch which depends
on a metal interrupter ring, mounted on the balancer to activate it. Windows in the interrupter activate the "hall-effect" switch as they provide a
path for the magnetic field between the switch's transducer and it's magnet.
OPERATION
When the "hall-effect" switch is activated, it grounds the signal line to the C3I module, pulling the crank signal line's applied voltage low which is
interpreted as a crank signal. Because of the way the signal by the crank sensor is created, the signal circuit is always either at a high or low
voltage (square wave signal) and three signal pulses are created during each crankshaft revolution. This signal issued by the C3I module to create a
reference signal which is also a "square wave" signal similar to the crank signal. The reference signal is used to calculate engine rpm and
crankshaft position by the Electronic Control Module (ECM).
