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System Component Description

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
GM3460746
Callout Component Name
KL9 ENG CONTROL: STOP/START SYS
KL9 ENG CONTROL: STOP/START SYS
B19B B19B Brake Booster Vacuum Sensor
K20 K20 Engine Control Module
B19B B19B Brake Booster Vacuum Sensor
K17 K17 Electronic Brake Control Module
M9 M9 Brake Booster Pump Motor

The Brake Booster Vacuum Assist system consists of the following:

Brake Booster Auxiliary Vacuum Pump (electric or mechanical)

The Brake Booster Vacuum Pump is a secondary vacuum supply to the brake booster used to maintain sufficient vacuum for brake assist.

Brake Booster Vacuum Sensor Without KL9

The vacuum sensor is used to measure the level of vacuum available in the brake booster. The Electronic Brake Control Module supplies a 5 V reference and a low reference circuit to the brake booster vacuum sensor. The vacuum sensor is located in the brake booster or vacuum hose. The Brake Booster Vacuum Sensor supplies a voltage signal in relation to the pressure in the brake booster to the Electronic Brake Control Module.

Brake Booster Vacuum Sensor With KL9

The vacuum sensor is used to measure the level of vacuum available in the brake booster. The Engine Control Module supplies a 5 V reference and a low reference circuit to the brake booster vacuum sensor. The vacuum sensor is located in the brake booster or vacuum hose. The Brake Booster Vacuum Sensor supplies a voltage signal in relation to the pressure in the brake booster to the Engine Control Module.

Electronic Brake Control Module

The Electronic Brake Control Module monitors the vacuum in the brake booster using the Brake Booster Vacuum Sensor. When the vacuum within the system drops, below 42 kPa (6 psi) the Electronic Brake Control Module turns ON the Brake Booster Auxiliary Vacuum Pump by providing a ground to the Brake Booster Pump Relay. The relay activates and supplies voltage to the Brake Booster Auxiliary Vacuum Pump. The Electronic Brake Control Module shuts the pump off when the vacuum pressure is above 55 kPa (8 psi) by removing the ground to the Brake Booster Pump Relay.

Vacuum Brake Booster

When brake system input force is applied, air at atmospheric pressure is admitted to the rear of both vacuum diaphragms, providing a decrease in brake pedal effort required. When input force is removed, vacuum replaces the atmospheric pressure within the booster. The booster uses source vacuum to decrease the effort required by driver when applying the brake.

Vacuum Source

Vacuum is supplied by the engine vacuum or by the Brake Booster Auxiliary Vacuum Pump.