Circuit Description
WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. 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 increases as speed increases. The transfer case shift control module converts the pulsating AC voltage to a propshaft RPM which is used for calculations, and to monitor the difference between the front and rear propshaft speed. It is also used in the AUTO 4WD mode of operation to determine the amount of slip and the percent of torque to apply to the front axle. The module only looks at this input when the vehicle is in AUTO 4WD mode, 4H, and 4L 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.