For 1990-2009 cars

# DIESEL HI PITCHED WHINE CRUISE CONTROL INFORMATION

EARLY PRODUCTION DIESEL EQUIPPED CARS MAY EXPERIENCE A HIGH PITCHED WHINE WITH CRUISE CONTROL ENGAGED. THIS WHINE MAY VARY SLIGHTLY AS THE CAR GOES UP AND DOWN HILLS. THE NOISE WILL STOP WHEN THE CRUISE CONTROL UNIT IS DISENGAGED. A RUNNING PRODUCTION CHANGE CORRECTED THIS CONDITION BY CHANGING THE SIZE OF THE VENT HOLE IN THE VACUUM REGULATOR, P/N 6466910. THE LATER DESIGN VACUUM REGULATOR IS IDENTIFIED WITH A GOLD COLORED COVER AND SHOULD BE USED TO CORRECT VEHICLES EXHIBITING THIS CONDITION . THE ORIGINAL VACUUM REGULATORS HAVE SILVER COLORED COVERS AND CAN BE USED FOR SERVICE ON VEHICLES WHICH ARE NOT AFFECTED.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.