Envoy 2WD V6-4.3L VIN W (1998)
Crankshaft Position Sensor: Description and Operation
Description
DESCRIPTION
The Crankshaft Position (CKP) Sensor is located in the front engine cover and is perpendicular to the crankshaft target wheel. The air gap between the
sensor and the wheel is preset and not adjustable. The target wheel has four slots 60 degrees apart and is keyed to the crankshaft. As the target wheel
rotates, the slots passing by the sensor create a change in the magnetic field of the sensor which results in an induced voltage pulse. One revolution of the
crankshaft results in four pulses (4x signal). Based on these pulses, the VCM is able to determine crankshaft position and engine speed. The VCM then
activates the fuel injector and provides a spark to the Distributor. The relation between the crankshaft position sensor and the target wheel is crucial. The
sensor must be exactly perpendicular to the target wheel with the correct air gap.
OPERATION
The crankshaft position sensor provides the VCM with the crankshaft speed and the crankshaft position. The VCM utilizes this information in order to
determine if an engine Misfire is present. The VCM monitors the CKP sensor for a momentary drop in the crankshaft speed in order to determine if a
misfire is occurring. When the VCM detects a misfire, a DTC P03OO will set.
DIAGNOSIS
The VCM also monitors the CKP sensor signal circuit for malfunctions. The VCM monitors CKP signal and the High and Low resolution signals. The
VCM calculates these signals in order to determine a ratio. When the VCM detects that the ratio is out of normal operating range, the VCM will set a
DTC P0337 or a DTC P0338.
