Optimized Hydraulic Braking

The ABS module incorporates a strategy called optimized hydraulic braking. This strategy uses the pump motor in the HCU to provide brake pedal boost in the event that the vacuum brake booster fails. The brake booster is equipped with a vacuum sensor. When vacuum in the booster falls below a predetermined level, a DTC is set in the ABS module. If the brake pedal is applied with low vacuum in the booster, the ABS module activates the pump motor in the HCU to assist with braking. During pump motor operation, the driver may feel a pulsation in the brake pedal, accompanied by a slight up and down movement in the pedal height. In addition, a mechanical noise may be heard.

Refer to POWER BRAKE ACTUATION for sensor removal and installation information.