Bleeding the ABS/TCS System
First perform a manual or pressure bleeding procedure. Refer to
Pressure Brake System Bleeding
in
Hydraulic Brakes. If the desired brake pedal height results are not achieved,
perform the auto bleed procedure below.
The auto bleed procedure is used on Delco Bosch 5 equipped vehicles.
The procedure cycles the system valves and runs the pump in order to purge
the air from the secondary circuits normally closed off during non ABS/TCS
mode operation and bleeding. The auto bleed procedure is recommended when
air ingestion is suspected in the secondary circuits, or when the BPMV has
been replaced.
Items Required
- A scan tool
- A 30 psi adapter equipped brake bleeder
- Delco Supreme 11 brake fluid
- A hoist
- An unbreakable plastic bleeder bottle equipped with a hose
- An assistant
- The suitable safety attire, including safety glasses
Auto 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.
- Raise the vehicle on a suitable support.
- Remove all four tire and wheel assemblies.
- Inspect the brake system for the following conditions. Repair
or replace as needed:
- Inspect the battery state of charge.
- Connect the scan tool to the DLC.
- Turn the ignition to ON position with the engine OFF.
- Using the scan tool, establish communications with the ABS/TCS
system.
Select the following features:
• | AUTOMATED BLEED PROCEDURE |
- Bleed the basic brake system. Refer to
Pressure Brake System Bleeding
in Hydraulic Brakes.
- Follow the scan tool directions until the desired brake pedal
height is achieved.
- 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 the appropriate DTC table. |
- When the desired pedal height is achieved, press the brake pedal
in order to inspect for firmness.
- Disconnect the scan tool.
- Install the tire and wheel assemblies.
- Inspect the brake fluid level.
- Road test the vehicle while making sure the brake pedal remains
high and firm.