Antilock Brake System Automated Bleed
Before performing the Automated Brake Bleed Procedure, first perform a pressure bleed of the base brake system. Hydraulic Brake System Bleeding The automated brake 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 Automated Brake 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 brake operation. The automated brake bleed procedure opens these secondary circuits and allows any air trapped in these circuits to flow out toward the brake corners.
Performing the Automated Brake Bleed Procedure
- Raise and support the vehicle. Lifting and Jacking the Vehicle (Standard Service) , or Lifting and Jacking the Vehicle (Mobile Service)
- Remove all four tire and wheel assemblies. Tire and Wheel Removal and Installation
- Inspect the brake system for leaks and visual damage. Repair or replace components as needed.
- Lower the vehicle.
- Inspect the battery state of charge. Battery Inspection/Test
- Install a scan tool.
- Place ignition into service mode.
- Remove key fob from vehicle and place out of range.
- With the scan tool, establish communications with the ABS system. Select Control Functions. Select Automated Brake Bleed from the Control Functions menu.
- Raise and support the vehicle. Lifting and Jacking the Vehicle (Standard Service) , or Lifting and Jacking the Vehicle (Mobile Service)
- Following the directions given on the scan tool, run the GDS - brake hydraulic test. If it fails, bleed the brake system. Hydraulic Brake System Bleeding
- Remove the scan tool.
- Install all four tire and wheel assemblies. Tire and Wheel Removal and Installation
- Remove the support and lower the vehicle.
- Inspect the brake fluid level. Brake Master Cylinder Reservoir Filling
- Road test the vehicle while inspecting that the pedal remains high and firm.
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.
Failure to place the key fob out of range will result in exiting service mode when the brake pedal is pressed.