Owner Letter
December, 1999Dear Chevrolet/GMC Customer:
As the owner of a General Motors truck equipped with the Lucas Varity three-sensor antilock brake system (ABS), your satisfaction with our product is of utmost concern to us.
Condition: The federal government's highway safety agency. the National Highway Traffic Safety Administration (NHTSA) has identifled1 and General Motors Corporation has confirmed the existence of a condition in the antilock braking system of some Chevrolet and GMC 1994-1996 S/T pickups equipped with a V6 engine and 1995-1996 S/T utility vehicles. On rare occasions, this condition can result in longer stopping distances during certain antilock brake applications, as explained below.
If you're driving on a road surface that supports good traction and you begin to stop by applying your brake pedal firmly, and both front wheels of your vehicle then pass, onto a slippery surface (such as an ice-covered or wet patched asphalt part of the road), your antilock brake system will adjust the brakes at each of the wheels to take advantage of the available traction. This will allow you to steer and maintain stability, which is normal ABS operation, as your owner's manual explains in more detail.
However, if you are still braking while the vehicle leaves the slippery surface and both front wheels get back on a higher-traction surface, the ABS may perform as if the vehicle were still on the slippery surface and the vehicle may not stop as quickly. However, this will not happen every time these conditions are encountered. It depends on several additional factors, such as vehicle speed and the length of the slippery surface.
Your ABS system was designed with increased sensitivity to wheel slip in order to improve vehicle steerability while braking on very slippery surfaces. This improvement for steerability, however, made it possible for reduced front braking effectiveness to occur as described above. Therefore, GM has developed a software change that will make your vehicle less Sensitive to wheel slip under the circumstances described above.
What Will Be Done: Upon your request, your Chevrolet/GMC dealer will make a change to your antilock braking system software to prevent this phenomenon from occurring. This software change will have only a slight effect on vehicle steerablity during braking on very slippery surfaces and is designed to have no effect on normal ABS or other braking operations. This change should not affect how your brakes feel or create any perceptible difference in the steerability or stability of your vehicle while braking. This modification will be performed for you at no charge at anytime until December 1, 2002.
How Long Will The Repair Take: Your Chevrolet/GMC dealer will modify your vehicle's ABS software. We estimate that it will take your dealer 45 minutes to perform this modification. Additional time may be required to schedule and process your vehicle. If your dealer has a large number of vehicles awaiting service, this additional time may be significant. Please ask your dealer if you wish to know how much additional time will be needed.
Contacting Your Dealer: Repairs and adjustments qualifying under this special coverage must be performed by a Chevrolet/GMC dealer. You may want to call the service department to arrange a convenient appointment. Should your dealer be unable to schedule a service date within a reasonable time, you should contact the appropriate Customer Assistance Center at the number listed below:
Deaf, Hearing Impaired
Division Number or Speech Impaired*
Chevrolet 1-800-222-1020 1-800-833-2438
GMC 1-800-462-8782 1-800-462-8583
* Utilizes Telecommunication Devices for the Deaf/Text Telephones (TDD/TTY)
1-800-462-8782. The deaf, hearing impaired, or speech impaired should call 1-800-462-8583 (utilizes Telecommunication Devices for the Deaf/Text Telephones, TDD/TTY).