For 1990-2009 cars

# AM RADIO BUZZ NOISE DURING THROTTLE OPERATION

Some 1983 vehicles equipped with a diesel engine may experience AM radio noise during part throttle operation with the TCC engaged. This noise, which sounds like "ignition" noise (a cracking, buzz noise) may be caused by vibrating or bouncing contacts in the vacuum regulator valve.

Replacing the vacuum regulator valve with one that has a Julian date stamp of 25321, or later, will correct this condition. The Julian date is stamped on the outboard side of the VRV. Refer to illustration for example.

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.