CAMPAIGN: REDUCED BRAKING ABILITY (BRAKE SYS. FAILURE)

GENERAL MOTORS HAS DETERMINED THAT A DEFECT WHICH RELATES TO MOTOR VEHICLE SAFETY EXISTS IN SOME 1982-84 B6P042 SCHOOL BUS CHASSIS AND 1984 P6T042 FORWARD CONTROL CHASSIS TRUCKS EQUIPPED WITH HY-POWER DUAL HYDRAULIC BRAKE SYSTEMS (RP0 JM7). IF THE PRIMARY BRAKE SYSTEM BOOSTER FAILS, THE ELECTRIC CONTROL MODULE FOR THE RESERVE BRAKE SYSTEM HYDRAULIC PUMP MAY ALSO FAIL UNDER CERTAIN CONDITIONS, RESULTING IN A SIGNIFICANT REDUCTION IN BRAKING ABILITY. SUCH A REDUCTION OF BRAKING ABILITY AT A TIME WHEN MINIMUM STOPPING DISTANCE IS REQUIRED COULD RESULT IN A VEHICLE CRASH WITHOUT PRIOR WARNING. TO CORRECT THIS CONDITION, IT WILL BE NECESSARY TO REMOVE AND REPLACE THE BRAKE CONTROL MODULE ASSEMBLY. VEHICLES INVOLVED INVOLVED ARE CERTAIN 1982-1984 B6P042 SCHOOL BUS CHASSIS AND 1984 P6T042 FORWARD CONTROL CHASSIS TRUCKS EQUIPPED WITH A HY-POWER DUAL HYDRAULIC BRAKE SYSTEM (RP0 JM7) AND BUILT WITHIN THE FOLLOWING VIN BREAKPOINTS: MODEL NO. YEAR FROM THROUGH B6P042 1982 CV562123 CV596821 B6P042 1983 DV500016 DV534776 B6P042 1984 EV500747 EV534130 P6T042 1984 EV504247 EV533425 CHECK THE C.R.I.S. SYSTEM TO DETERMINE IF A SPECIFIC VEHICLE IS INVOLVED IN THIS CAMPAIGN. SERVICE PROCEDURE 1. WITH IGNITION KEY IN "OFF" POSITION, DISCONNECT NEGATIVE BATTERY CABLE. 2. LOCATE BRAKE CONTROL MODULE ASSEMBLY ON VEHICLE (SEE FIGURE 1). NOTE: IT MAY BE NECESSARY TO REMOVE KICK PANEL, LOCATED TO THE LEFT OF THE DRIVERS FEET, ON SOME SCHOOL BUS MODELS. 3. HAVING LOCATED MODULE ASSEMBLY, FOLLOW HARNESS AND DISCONNECT 3 CONNECTORS LOCATED APPROXIMATELY 18" FROM MODULE AND FOURTH CONNECTION AT BRAKE SWITCH. 4. LOOSEN 2 RETAINING SCREWS TO REMOVE MODULE FROM VEHICLE. DISCARD REMOVED MODULE. 5. INSTALL NEW BRAKE CONTROL MODULE ASSEMBLY, P/N 15520923, FOLLOWING REMOVAL PROCEDURE IN REVERSE ORDER. PARTS INFORMATION PARTS ARE TO BE OBTAINED FROM THE WAREHOUSING AND DISTRIBUTION DIVISION OF GENERAL MOTORS (WDDGM). TO ENSURE THAT THESE PARTS WILL BE OBTAINED AS SOON AS POSSIBLE, THEY SHOULD BE ORDERED FROM WDDGM ON A C.I.O. ORDER WITH NO SPECIAL INSTRUCTION CODE, BUT ORDER ON AN ADVISE CODE. (2). ALL VEHICLES INVOLVED IN THIS CAMPAIGN WILL REQUIRE THE FOLLOWING PART: PART NUMBER DESCRIPTION QTY. PER VEHICLE 15520923 BRAKE CONTROL 1 MODULE ASSEMBLY

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.