GM Service Manual Online
For 1990-2009 cars only

UNWANTED 3-2 DOWNSHIFTS CRUISE CONTROL LINKAGE ADJ.

A CONDITION OF AN UNWANTED 3-2 DOWNSHIFT AND EXCESSIVE ENGINE NOISE OCCURRING DURING THE CRUISE CONTROL RESUME OR ACCELERATE MODES MAY BE CAUSED BY A MALADJUSTED CRUISE CONTROL LINK OR CHAIN. IF THE TRANSMISSION SHIFT POINTS ARE NORMAL WHEN NOT USING CRUISE CONTROL, A SLIGHT AMOUNT OF SLACK (ONE OR TWO BEADS OR HOLES) SHOULD BE ADDED TO THE CRUISE CONTROL LINKAGE. THROTTLE POSITION (PARAMETER .0.1) SHOULD NOT EXCEED 60F AT ANY TIME AFTER RESUME IS DEPRESSED AT 35 MPH TO ACCELERATE TO A PREVIOUSLY ESTABLISHED 55 MPH SET SPEED. A TRADE-OFF EXISTS IN THAT THE VEHICLE MAY LOSE SEVERAL MILES PER HOUR WHILE GOING UPHILL IN CRUISE CONTROL IF THE CRUISE LINKAGE IS READJUSTED TO AVOID AN UNWANTED 3-2 DOWNSHIFT.

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.