ABS Bleed Procedure

PREPARATION PROCEDURE
The Auto Bleed Procedure provides a complete brake system bleed on Teves Mark IV equipped vehicles.

The procedure cycles the system valves and runs the pump in order to purge air from secondary circuits. These secondary circuits are normally closed off during non-ABS/TCS mode operation and bleeding.

Use the Auto Bleed Procedure under either of the following conditions:
^ When it is suspected that air has been ingested into the system secondary circuits.
^ When the Brake Pressure Modulator Valve (BPMV) has been replaced with a new unit.

The following tools and aids are required in order to successfully perform the procedure:
^ The Scan Tool.
^ A pressure brake bleeder which can produce at least 30 psi and which has suitable adapters.

The pressure brake bleeder must be filled with Delco Supreme 11 brake fluid which was obtained from a sealed container.
^ A hoist or suitable stands with which to support the vehicle.
^ A bleeder bottle to receive the vented brake fluid.

The bottle should meet the following construction requirements:
- The bottle should be constructed of unbreakable plastic.
- The bottle should have a clear plastic hose which is sized to fit snugly onto the bleeder valves.
- The hose should protrude into the bottle with its end immersed in brake fluid.
^ An assistant to pump the brake pedal during the procedure
^ Suitable safety attire, including safety glasses.

BLEEDING 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 pressing EXIT relive bleed pressure and disconnect bleed equipment manufacturers instructions.

1. Suitably support and raise the vehicle.
2. Remove all four wheels.
3. Inspect the brake system for leaks or component damage. Correct any problems before beginning the procedure.
4. Ensure that the vehicle battery is fully charged.
5. Connect the Scan Tool to the DLC.
6. Turn the ignition to RUN. Do not start the engine.
7. Establish communications with the Scan Tool.
8. Select ABS/TCS system features.
9. Select MISCELLANEOUS TESTS.
10. Select AUTOMATED BLEED PROCEDURE.
11. Bleed the brake system. Refer to Bleeding.
12. Follow the Scan Tool menu driven instruction in order to achieve the proper brake pedal height.
^ If any malfunctions are detected, the bleed procedure will be aborted.
^ If DTCs are present, the Scan Tool will either display the message DTCs PRESENT or list the DTCs. (This depends on when the DTCs were set.) DTCs may be displayed or cleared, as appropriate, in the Trouble Codes mode. Refer to the applicable section for each DTC.
^ If the test is aborted but no DTCs are listed, refer to "Diagnostic System Check" in Antilock Brake System/Testing and Inspection

Correct all system malfunctions, and attempt the bleed procedure again.

If a road test is required for diagnosis and the brake pedal is spongy, perform a conventional brake bleed. Achieve a firm pedal before driving the vehicle.

13. When the Auto Bleed Procedure is complete, depress the brake pedal.
^ The pedal should be high and firm. If the pedal is not high and firm, reinspect the brake system thoroughly for any conditions that may cause excess brake pedal travel. Refer to ABS/TCS Troubleshooting.
^ If the brake system is OK but excess pedal travel exists, repeat the Auto Bleed Procedure.

14. Disconnect the Scan Tool.
15. Reinstall the wheels and the tires.
16. Lower the vehicle.
17. Check the brake fluid level in the reservoir. Fill the reservoir if necessary.
18. Road test the vehicle.
^ Make several ABS and TCS actuations in a suitable area.
^ The brake pedal should remain high and firm after the road test.