Circuit Description

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including 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 steering wheel position sensor produces 2 separate voltage signals to indicate steering wheel position to the Real Time Damping (RTD) module. The RTD module converts each signal into a Pulse Width Modulated (PWM) signal to indicate steering wheel position to the EBCM. The EBCM supplies 5 volts to the RTD module on each steering wheel position PWM serial data circuit. The RTD module toggles each of these voltages to ground in order to create the PWM signals. Each PWM signal must have a frequency of 121-134 Hz and a duty cycle of 9-91 percent in order to be a valid steering wheel position signal. With each 360 degree rotation of the steering wheel, each signal transitions from the minimum duty cycle to the maximum duty cycle and then back to the minimum duty cycle. The steering wheel position signals are spaced 90 degrees apart. Therefore, the duty cycles of the 2 signals usually differ, depending on steering wheel position.