ABS PEDAL PULSATION NEW WHEEL SPEED SENSOR. Cadillac Fleetwood 1991

THIS BULLETIN IS BEING REVISED TO ADD 1992 MODEL YEAR, ADD NEW PART NUMBER FOR WHEEL SPEED SENSOR, MODIFY THE CONDITION AND DIAGNOSIS AND CORRECTION SECTIONS, AND ADD WARRANTY INFORMATION.

REVISION 10/25/93

THIS BULLETIN IS BEING REVISED TO UPDATE PART NUMBER, SERVICE PROCEDURE AND WARRANTY INFORMATION FOR REAR WHEEL SPEED SENSORS. ----------------------------------------------------------------------

PREVIOUS DIVISIONAL PUBLICATION NUMBERS WERE:

BUICK 92-5-11 CADILLAC T-92-123 GM OF CANADA 92-5-118 OLDSMOBILE 92-T-121 PONTIAC 92-5-19 ********************************************************************

SUBJECT: ABS BRAKE PEDAL PULSATION WHEN APPLYING BRAKES (NEW REAR WHEEL SPEED SENSORS)

MODELS & VIN BREAKPOINTS:

1991 1992 BUICK PARK AVE/ULTRA - ALL BUICK PARK AVE/ULTRA - SOP-N1658452 OLDSMOBILE 98 - ALL OLDSMOBILE 98 - SOP-N4342200 CADILLAC DEVILLE - ALL CADILLAC DEVILLE - SOP-N4320770 BUICK LESABRE - ALL W/JM4 BUICK LESABRE - SOP-NH529587 OLDSMOBILE 88 - ALL W/JM4 OLDSMOBILE 88 (W) - SOP-N1829500 PONTIAC BONNEVILLE- ALL W/JM4 OLDSMOBILE 88 (BC) - SOP-NH374781 PONTIAC BONNEVILLE - SOP-N1308405

CONDITION:

OWNERS MAY NOTICE BRAKE PEDAL VIBRATION (ABS CYCLING) AND THE PEDAL MAY DROP APPROXIMATELY ONE INCH AT THE END OF A BRAKE STOP. THIS USUALLY HAPPENS WHEN DECELERATING BELOW 10 MPH AND THE BRAKES ARE NOT APPLIED HARD ENOUGH AND ROAD CONDITIONS ARE NOT SUCH TO ACTIVATE THE ANTILOCK SYSTEM.

CAUSE:

THIS CONDITION MAY BE CAUSED BY MOISTURE INTRUSION INTO THE REAR WHEEL SPEED SENSOR.

CORRECTION:

THE PEDAL VIBRATION (ABS CYCLING) DUE TO MOISTURE INTRUSION MAY OR MAY NOT SET A TROUBLE CODE. USE A TECH 1 OR CAMS TO READ ANY TROUBLE CODES THAT MAY BE STORED IN THE EBCM. FOLLOW THE SERVICE MANUAL PROCEDURE TO REPAIR ANY STORED CODES.

WHETHER REAR WHEEL SPEED SENSOR CODES ARE STORED OR NOT, REPLACE BOTH REAR WHEEL SPEED SENSORS AS FOLLOWS:

1. RAISE VEHICLE AND SUITABLY SUPPORT (REFER TO SECTION 0A OF THE SERVICE MANUAL). 2. REMOVE ONLY THE REAR LOWER STRUT ATTACHING NUT AND BOLT. 3. CLEAN ALL DIRT AND DEBRIS FROM SENSOR HOUSING/SENSOR INTERFACE AREA. 4. DISCONNECT REAR WHEEL SPEED SENSOR CONNECTOR (FIGURE 2, #4). 5. USING TOOL J39860 (TOOL SUPPLIED BY CADILLAC LUXURY CAR DIVISION, CLCD, FREE OF CHARGE) (FIGURE 1), A 1/4 INCH DRIVE RATCHET AND 10 INCH EXTENSION, REMOVE THREE TORX SCREWS AND DISCARD OLD SENSOR. IF A TORX SCREW BREAKS OR STRIPS OUT, THE COMPLETE HUB AND BEARING ASSEMBLY MUST BE REPLACED. REFER TO SECTION 3D OF THE APPLICABLE SERVICE MANUAL FOR REAR HUB AND BEARING REPLACEMENT PROCEDURE. IF ALL TORX SCREWS CAN BE REMOVED, PROCEED TO STEP 6. 6. REMOVE REAR WHEEL SPEED SENSOR (FIGURE 2, #2). USE A CLEAN SOFT CLOTH TO CLEAN ANY DIRT OR FOREIGN MATERIAL FROM THE SENSOR HOUSING SURFACE. 7. DISCARD OLD SEAL FROM WIRING HARNESS CONNECTOR. USE A CLEAN, SOFT CLOTH TO REMOVE ALL DIRT AND MOISTURE AROUND THE OLD SEAL CONNECTOR. 8. LUBE NEW SENSOR O-RING WITH LUBE SUPPLIED IN SERVICE KIT, P/N 10457129, AND INSTALL NEW SENSOR TO HOUSING. NOTE: DO NOT ALLOW DEBRIS TO ENTER SENSOR HOUSING. DO NOT ADD LUBRICANT TO THE BEARING THROUGH SENSOR HOUSING OPENING. DO NOT CLEAN GREASE FROM THE TOOTHED SENSOR RING. 9. INSTALL LOOSELY, THREE NEW SENSOR ATTACHING SCREWS. TIGHTEN SENSOR ATTACHING SCREWS TO 2.8 N.M (25 LB. IN.) IN THE ORDER SHOWN IN FIGURE 2, USING TOOL J39860. 10. INSTALL NEW SEAL ONTO EXISTING CONNECTOR BODY. 11. INSTALL CONNECTOR (FIGURE 2, #4) TO REAR WHEEL SPEED SENSOR. NOTE: THE CONNECTOR BODIES ARE SHAPED TO ONLY ALLOW INSTALLATION ONE WAY. INSTALL CONNECTOR SO THAT LATCHES ON CONNECTOR SNAP OVER TABS ON SENSOR. 12. INSTALL LOWER STRUT ATTACHING BOLT AND NUT, TIGHTEN TO 190 N.M (140 LB. FT.). 13. REPEAT STEPS 2 THROUGH 12 FOR OPPOSITE REAR WHEEL SPEED SENSORS. 14. LOWER VEHICLE.

CLEAR CODES AND ROAD TEST THE VEHICLE BEFORE REPLACING ANY OTHER ANTILOCK SYSTEM COMPONENT.

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

REPLACE BOTH REAR WHEEL SPEED SENSORS ON VEHICLE.

LABOR OPERATION NUMBER: T5305 LABOR TIME: 0.7

IF HUB AND BEARING ASSEMBLY(IES) REPLACEMENT IS REQUIRED, REFER TO LABOR TIME GUIDE FOR APPLICABLE E-OPERATION NUMBER.

FIGURES: 2

Object Number: 94083 Size: MF

Object Number: 84290 Size: FS

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.