By Greg R. Whale
As electronics provide the means to distract drivers, they also can counteract such distractions to make vehicles safer. The marriage of data streams and mechanical parts introduced stability systems in the mid '90s, and for '03, GM has taken StabiliTrak to the next level.
Through '02 models, StabiliTrak was a two-channel system and available only on the Cadillac Escalade and EXT. However, the StabiliTrak moniker is not limited to Cadillac, and for '03, the system will be standard on AWD Escalades and Denalis and optional on all GM 5.3L 1500-series SUVs (Tahoe, Suburban, Avalanche, and Yukon XL). Expect it to be competitively priced.
StabiliTrak is similar to many electronic stability systems offered on luxury cars and premium utilities. By gathering input data from sensors for individual wheel speed, yaw rate, lateral acceleration, throttle position, gear, transfer-case controller (for front/rear driveshaft speeds and gear range), instrument cluster, brake-fluid pressure, and steering-wheel angle, a computer compares the scenario to known limits in its algorithm. From there, the computer signals the electronic throttle and hydraulic-brake systems to take corrective measures. This action may include limiting engine output (torque management), application of the brakes at any single or combination of wheels, or both. Most of the noise people hear or feel when a stability system is operating is the hydraulic-fluid pump building pressure and cycling the brake(s) much like an antilock system does.