GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • Scan Tool
    • J 29532 Diaphragm Pressure Bleeder with the proper master cylinder adapter
    • Delco Supreme 11 or equivalent Dot 3 brake fluid from a clean, sealed container
    • A hoist
    • An unbreakable plastic bleeder bottle equipped with a hose to recover fluid at the wheels
    • An assistant, if needed
    • The suitable safety attire, including safety glasses

Perform the automated ABS bleed procedure whenever one of the following conditions occurs:

    • Manual bleeding at the wheel cylinders does not achieve the desired pedal height or feel.
    • The Brake Pressure Modulator Valve (BPMV) is replaced.
    • Extreme loss of brake fluid has occurred.
    • Air ingestion is suspected.

If none of the above conditions applies, use standard bleed procedures. Refer to Hydraulic Brake System Bleeding in hydraulic brakes.

This procedure uses a scan tool in order to cycle the system solenoid valves and to run the pump motor in order to purge the air from the secondary circuits. These secondary circuits are normally closed, 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 inside the BPMV to flow out toward the wheel cylinders or the calipers where the air can be purged out of the system.

Automated Bleed Procedure

Preliminary Inspection

  1. Inspect the battery for full charge, repair the battery and charging system as necessary. Refer to Charging System Test in Engine Electrical.
  2. Connect a scan tool to the DLC connector and select Current and History DTCs. Repair any DTCs prior to performing the ABS bleed procedure.
  3. Inspect for visual damage and leaks, repair as needed.

Preliminary Setup

  1. Raise and support the vehicle on a suitable support. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Turn the ignition switch to the OFF position.
  3. Connect the J 29532 according to the manufacturer's instructions.
  4. Turn the ignition switch to ON position, engine OFF.
  5. Connect a scan tool and establish communications with the ABS system.
  6. Remove all 4 tires, if necessary.
  7. Pressurize the bleeding tool to 35 psi.

Performing the 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. With the J 29532 at 35 psi, and all bleeder screws in closed position, select Automated Bleed Procedure on the scan tool and follow the instructions.
  2. The first part of the automated bleed procedure will cycle the pump and front release valves for 1 minute. After the cycling has stopped the scan tool will enter a cool down mode and display a 3-minute timer. The auto bleed will not continue until this timer expires. You cannot override this timer.
  3. The scan tool will request the technician to open one of the bleeder valves. The scan tool will then cycle this valve and the pump motor for 1 minute.
  4. The scan tool repeats step 3 for the remaining bleeder valves.
  5. With the J 29532 still attached to the vehicle and maintaining 35 psi, the scan tool will instruct the technician to independently open each bleeder screw for approximately 20 seconds. This should allow any remaining air to be purged from the brake pipes.
  6. When the automated bleed procedure is completed, the scan tool will display the appropriate message.
  7. Remove pressure from the J 29532 and then disconnect J 29532 from the vehicle.
  8. Depress the brake pedal in order to gauge the pedal height and feel.
  9. Repeat steps 1-8 until the pedal is acceptable.
  10. Remove the scan tool from the DLC.
  11. Install the tire and wheel assemblies, if removed.
  12. Lower the vehicle.
  13. Inspect the brake fluid level in the master cylinder.
  14. Road test the vehicle while verifying that the brake pedal remains high and firm.