Brakes - Pedal Pulsation When Applying ABS
Bulletin: 92-5-11Date: July '92
Ref. No.: 92-242-5
Corp. Ref. No.: 105002R
SUBJECT:
ABS BRAKE PEDAL PULSATION WHEN APPLYING BRAKES (NEW WHEEL SPEED SENSOR)
MODELS AFFECTED:
1991-92 PARK AVENUE/ULTRA
1991-92 LESABRE
THIS BULLETIN IS BEING REVISED TO ADD 1992 MODEL YEAR AND TO ADD NEW PART NUMBER FOR WHEEL SPEED SENSOR, MODIFY THE CONDITION AND DIAGNOSIS AND CORRECTION SECTIONS, AND ADD WARRANTY INFORMATION. PLEASE DISCARD BULLETIN NO. 91-5-8 AND REPLACE IT WITH THIS BULLETIN.
VIN BREAKPOINTS INVOLVED ARE:
1991 1992
PARK AVE/ULTRA - ALL PARK AVE/ULTRA SOP-N1658452
LESABRE - ALL W/JM4 LESABRE SOP-NH529587
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.
DIAGNOSIS AND CORRECTION:
The pedal vibration (ABS cycling) due to moisture intrusion may or may not set a trouble code. Use a Tech I or CAMS to read any trouble codes that may be stored in the EBCM. Follow the service manual procedure to repair any stored codes.
If any of the rear wheel speed sensor codes are stored or if no trouble codes are stored, replace both rear wheel speed sensors, clear codes, and road test the vehicle before replacing any other Antilock System Component.
REPLACEMENT PARTS:
A new rear wheel speed sensor kit, Part No. 10457166 (1 per box) has been released for service. This sensor can be identified from previous (grey) sensor by the BLACK color.
Parts are currently available from GMSPO.
WARRANTY INFORMATION:
Labor Operation No.:
T5305
Labor Time:
1.2 hr.
Replace both sensors - add .1 hr. Wire Wheel Covers