Circuit/System Description

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

The crankshaft position (CKP) sensor contains 2 hall-effect switches in one housing. This sensor configuration produces 2 separate CKP sensor pulses. These pulses occur when 2 interrupter rings, mounted to the crankshaft balancer, the outer one containing 18 evenly spaced windows and blades, the inner one containing 3 unevenly spaced windows and blades, pass by the sensors. The 18X sensor produces 18 pulses per engine revolution. The 3X sync sensor produces 3 pulses per engine revolution, each pulse representing a pair of companion cylinders. Both sensors are connected directly to the ignition control (IC) module. The sensor wiring includes the following circuits:

The CKP sensor 1 signal circuit
The CKP sensor 2 signal circuit
A shared 12-volt reference circuit
A shared low reference circuit
A medium resolution engine speed signal circuit

The IC module uses the sensors to determine the engine position and speed. A signal converter within the IC module, using the 18X CKP sensor 1, produces a digital 18X output signal to the powertrain control module (PCM) on the medium resolution engine speed signal circuit. The PCM monitors the medium resolution engine speed signal circuit for errors.