Circuit Description

WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The front propshaft speed sensor is a permanent magnet (PM) generator. The PM generator produces a pulsing AC voltage. The AC voltage level and number of pulses increase as speed increases. The transfer case shift control module converts the pulsating AC voltage to a propshaft RPM, which is used for the following functions:

Calculations
To monitor the difference between the front and rear propshaft speed
In the AUTO or the Adapt mode of operation, to determine the amount of slip and the percent of torque to apply to the front axle

The module accesses this input when the vehicle is in AUTO mode, 4HI and 4LO ranges. The propshaft RPM can be displayed with a scan tool.

This DTC detects an open, short to ground, short to voltage or faulty sensor.