LaCrosse V6-3.8L (2009)
Brake Bleeding: Service and Repair
Antilock Brake System Automated Bleed Procedure
Antilock Brake System Automated Bleed Procedure
Warning: Refer to Brake Fluid Irritant Warning (See: Brakes and Traction Control/Service Precautions/Technician Safety Information/Brake
Fluid Irritant Warning).
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution (See: Brakes and Traction Control/Service Precautions/Vehicle
Damage Warnings).
Note: Before performing the ABS Automated Bleed Procedure, first perform a pressure bleed of the base brake system. Refer to Hydraulic Brake
System Bleeding (Pressure) (See: )Hydraulic Brake System Bleeding (Manual) (See: ). The automated bleed procedure is recommended when one of
the following conditions exist:
*
Base brake system bleeding does not achieve the desired pedal height or feel
*
Extreme loss of brake fluid has occurred
*
Air ingestion is suspected in the secondary circuits of the brake modulator assembly
The ABS Automated Bleed Procedure uses a scan tool to cycle the system solenoid valves and run the pump in order to purge any air from the secondary
circuits. These circuits are normally closed off, and are only opened during system initialization at vehicle start up and during ABS operation. The
automated bleed procedure opens these secondary circuits and allows any air trapped in these circuits to flow out toward the brake corners.
Performing the Automated Bleed Procedure
Caution: The Auto Bleed Procedure may be terminated at any time during the process by pressing the EXIT button. No further Scan Tool
prompts pertaining to the Auto Bleed procedure will be given. After exiting the bleed procedure, relieve bleed pressure and disconnect bleed
equipment per manufacturers instructions. Failure to properly relieve pressure may result in spilled brake fluid causing damage to components and
painted surfaces.
1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (See: Vehicle Lifting/Service and Repair).
2. Remove all four tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation (See: Wheels and Tires/Service and Repair).
3. Inspect the brake system for leaks and visual damage. Refer to Symptoms - Hydraulic Brakes (See: Brakes and Traction Control/Hydraulic
System/Testing and Inspection/Symptom Related Diagnostic Procedures/Symptoms - Hydraulic Brakes). Repair or replace components as needed.
4. Lower the vehicle.
5. Inspect the battery state of charge. Refer to Battery Inspection/Test (See: Starting and Charging/Testing and Inspection/Component Tests and
General Diagnostics/Battery Inspection/Test).
6. Install a scan tool.
7. Turn the ignition ON, with the engine OFF.
8. With the scan tool, establish communications with the ABS system. Select Special Functions. Select Automated Bleed from the Special Functions
menu.
9. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (See: Vehicle Lifting/Service and Repair).
10. Following the directions given on the scan tool, pressure bleed the base brake system. Refer to Hydraulic Brake System Bleeding (Pressure) (See:
)Hydraulic Brake System Bleeding (Manual) (See: ).
11. Follow the scan tool directions until the desired brake pedal height is achieved.
12. If the bleed procedure is aborted, a malfunction exists. Perform the following steps before resuming the bleed procedure:
*
If a DTC is detected, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Diagnostic Trouble Code Descriptions) , and diagnose the appropriate DTC.
*
If the brake pedal feels spongy, perform the conventional brake bleed procedure again. Refer to Hydraulic Brake System Bleeding (Pressure)
(See: )Hydraulic Brake System Bleeding (Manual) (See: ).
13. When the desired pedal height is achieved, press the brake pedal to inspect for firmness.
14. Lower the vehicle.
15. Remove the scan tool.
16. Install the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation (See: Wheels and Tires/Service and Repair).
17. Inspect the brake fluid level. Refer to Master Cylinder Reservoir Filling (See: Brakes and Traction Control/Hydraulic System/Brake Master
Cylinder/Service and Repair/Procedures/Master Cylinder Reservoir Filling).
18. Road test the vehicle while inspecting that the pedal remains high and firm.
