Antilock Brake System Automated Bleed Procedure. Chevrolet PJJ 2000

For 1990-2009 cars

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

#### Items Required

• | A scan tool

• | The J 29532 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

#### Preliminary Inspection

1. Inspect the battery for full charge, repair the battery and charging system as necessary. Refer to Charging Low or Completely Discharged Battery 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 hoist. Refer to Lifting and Jacking the Vehicle in General Information.
2. Turn the ignition switch to the OFF position.
3. Connect the J 29532 pressure bleeder according to the manufacturer's instructions.
4. Turn the ignition switch to the ON position, engine OFF.
5. Connect a scan tool and establish communication with the ABS system.
6. 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 pressure bleeder at 35 psi, and all the bleeder screws in the closed position, select the 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 the 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 pressure bleeder 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 pressure bleeder and then disconnect the J 29532 pressure bleeder 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. Lower the vehicle.
12. Inspect the brake fluid level in the master cylinder.
13. Road test the vehicle while verifying that the brake pedal remains high and firm.