ABS - Information Concerning Self-Test Noise

91olds03

NUMBER: 91-T-61

CORP.REF.NO: 175001

DATE: February 1991

SECTION: 5E


SUBJECT INFORMATION CONCERNING ABS NOISE SELF-TEST
NORMAL AFTER AN IGNITION SWITCH CYCLE


MODELS/YEARS 1989-91 OLDSMOBILE MODELS WITH ABS


All anti-lock brake systems (ABS) will perform a self-test called initialization during acceleration after each ignition switch cycle.

During this test, the modulator exercises the valves, solenoids and motor as the system monitors all inputs and outputs. This test is initiated at a relatively low speed so the ABS can be deactivated in the event there is an abnormal condition detected. Depending on the application, initialization occurs at different speeds, (usually 3 to 8 MPH) and will vary in intensity.

As it is possible to hear and feel the initialization cycle, some customers may comment about it. Initialization is a normal condition. Therefore, repair should not be attemped.