STEPPER MOTOR CRUISE RADIO FREQUENCY INTERFERENCE. Chevrolet Cavalier 1995

SUBJECT: STEPPER MOTOR CRUISE RADIO FREQUENCY INTERFERENCE (RFI) WITH LOW LAND MOBILE BAND RADIOS (REPLACE MODULE)

MODELS: 1995 BUICK SKYLARK 1995 CHEVROLET BERETTA, CAVALIER AND CORSICA 1995 OLDSMOBILE ACHIEVA 1995 PONTIAC GRAND AM AND SUNFIRE (FLEET VEHICLES ONLY - SEE BELOW FOR COMPLETE LIST)

CONDITION:

SOME FLEET CUSTOMERS MAY COMMENT ON POOR PERFORMING TWO-WAY RADIOS.

CAUSE:

RADIO FREQUENCY EMISSIONS ARE PRODUCED BY THE STEPPER II CRUISE CONTROL MODULE WHEN THE VEHICLE IGNITION IS ON. THE EMISSIONS ARE IN THE 30 - 50 MHZ BAND, WHICH IS REFERRED TO AS THE LOW LAND MOBILE BAND RADIO. THIS BAND IS USED BY BUSINESSES AND GOVERNMENT AGENCIES FOR COMMUNICATION USING TWO-WAY RADIOS WHICH ARE INSTALLED AS AFTER MARKET OPTIONS.

THIS INTERFERENCE REDUCES THE AUDIO QUALITY OF THE RECEPTION IN THE VEHICLE AND ALSO REDUCES THE RANGE AT WHICH THE VEHICLE CAN RECEIVE COMMUNICATIONS. THE TYPICAL LAND MOBILE USER IN A VEHICLE CAN COMMUNICATE WITH A BASE STATION AT A MAXIMUM RANGE OF APPROXIMATELY 65 MILES WITH NO INTERFERENCE.

THE FOLLOWING CHART ILLUSTRATES THE EFFECTS FOR EACH PLATFORM:

PLATFORM RANGE WITH RFI RANGE WITHOUT RFI ======== ============== =================

J 12.7 MILES 65 MILES L 18.0 MILES 65 MILES N 9.4 MILES 65 MILES

THE FLEET VEHICLES THAT WILL BE AFFECTED BY THE STEPPER II MODULE ARE: FORESTRY/CONSERVATION, GOVERNMENT (LOCAL, STATE AND FEDERAL) PETROLEUM, FIRE DEPARTMENTS, AND TAXIES. THIS CONDITION DOES NOT AFFECT RENTAL FLEETS OR ANY OTHER FLEET VEHICLE NOT MENTIONED.

CORRECTION:

A CRUISE CONTROL MODULE, P/N 25162818, HAS BEEN DESIGNED THAT REDUCES INTERFERENCE WITH THE LOW LAND MOBILE BAND RADIOS. FLEET VEHICLES WITH THE NEW CRUISE CONTROL MODULE MAY BE ORDERED ON A LIMITED BASIS UNTIL JANUARY, 1995. AFTER JANUARY, 1995, THE REVISED CRUISE CONTROL MODULE WILL BE INSTALLED IN ALL VEHICLES INTENDED TO BE BUILT WITH THE CRUISE CONTROL OPTION (K34).

PARTS AVAILALBILITY:

PARTS ARE EXPECTED TO BE AVAILABLE ON JANUARY 2, 1995.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OPERATION NUMBER: R1220 USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 0

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.