Antilock Brake System Automated Bleed Procedure

ANTILOCK BRAKE SYSTEM AUTOMATED BLEED PROCEDURE

Bleeding the ABS System

Caution: Brake fluid may irritate eyes and skin. In case of contact, take the following actions:
- Eye contact--rinse thoroughly with water.
- Skin contact--wash with soap and water.
- If ingested--consult a physician immediately.

Notice: Avoid spilling brake fluid onto painted surfaces, electrical connections, wiring, or cables. Brake fluid will damage painted surfaces and cause corrosion to electrical components. If any brake fluid comes in contact with painted surfaces, immediately flush the area with water. If any brake fluid comes in contact with electrical connections, wiring, or cables, use a clean shop cloth to wipe away the fluid.

Important:
* Before performing the ABS Automated Bleed Procedure, first perform a manual or pressure bleed of the base hydraulic brake system.
Refer to Hydraulic Brake System Bleeding - Manual Service and Repair
Refer to Hydraulic Brake System Bleeding - Pressure Service and Repair

The procedure cycles the system valves and runs the pump in order to purge the air from the secondary circuits normally closed off during normal base brake operation and bleeding. The automated bleed procedure is recommended when air ingestion is suspected in the secondary circuits, or when the BPMV has been replaced.

Automated Bleed Procedure

Notice: 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 the vehicle on a suitable support. Refer to Lifting and Jacking the Vehicle.
2. Remove all four tire and wheel assemblies.
3. Inspect the brake system for leaks and visual damage. Refer to Brake Fluid Loss or Symptoms - Hydraulic Brakes. Repair or replace as needed.
4. Inspect the battery state of charge. Refer to Battery Inspection/Test.
5. Install a scan tool.
6. Turn ON the ignition, with the engine OFF.
7. With the scan tool, establish communications with the EBCM. Select Special Functions. Select Automated Bleed from the Special Functions menu.
8. Bleed the base brake system. Refer to Hydraulic Brake System Bleeding (Manual), (Pressure).
9. Follow the scan tool directions until the desired brake pedal height is achieved.
10. 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, to diagnose the appropriate DTC.
^ If the brake pedal feels spongy, perform the conventional brake bleed procedure again.
11. When the desired pedal height is achieved, press the brake pedal in order to inspect for firmness.
12. Remove the scan tool.
13. Install the tire and wheel assemblies.
14. Inspect the brake fluid level. Refer to Master Cylinder Reservoir Filling.
15. Road test the vehicle while inspecting that the pedal remains high and firm.