Brakes - ABS Pump Self-Check Noise Explanation

Group:
CHASSIS

Number:
06-50-003

Date:
MARCH, 2006

Model:
1999 TO CURRENT AZERA, SANTA FE, TUCSON AND SONATA

Subject:
ABS PUMP SELF-CHECK NOISE

DESCRIPTION:

The Anti-lock Brake System (ABS) performs a hydraulic pump self-check test during the first acceleration after each ignition switch cycle. During this test, the ABS control module tests the pump modulator valves, solenoids and motor operation. This test occurs at a vehicle speed between 0 and 8 mph. During this test, a noise (customers may describe a rattle, groan, growl or gurgling) may be heard and felt through the brake pedal. This momentary noise is only heard during the initial period of vehicle motion. If any faults are found, the system disables the anti-lock braking function and will illuminate the warning lamp and set a diagnostic trouble code.

The purpose of this bulletin is to emphasize that this noise is the result of a normal function self-check test and it cannot be eliminated by replacing the Hydraulic Electronic Control Unit (HECU).

NOTE:
The HECU interactive pump self-diagnostic test and the related pump activation noise does not affect the ABS operation.