Volt

Antilock Brake System Automated Bleed

Special Tools

For equivalent regional tools, refer to Special Tools .

Warning: At times during this brake bleed procedure brake fluid will be under higher pressures than during typical brake bleed procedures. Ensure the bleeder hose attached to the bleeder valve is securely maintained in position whenever the bleeder valve is opened. Failure to maintain the bleeder hose securely to the valve when opened, may allow the hose to blow off and brake fluid to spray out of the bleeder valve, possibly resulting in personal injury.

Caution: Only use products that comply with GM specifications and check manufacturer information respectively. We recommend the use of GM genuine products. Instructions must be followed at all times. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution in the Preface section.

Note: 

Note: The transmission must be in the PARK position, the power button in the OFF position, and the brakes not applied to ensure the brake modulator and high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1 to 3 minutes.

1. Place the transmission in PARK.
2. Place the power button in the OFF position.
3. Wait approximately 3 minutes for the HPA pressure relief to occur.

Danger: Do not use a service jack in locations other than those specified to lift this vehicle. Lifting the vehicle with a jack in those other locations could cause the vehicle to slip off the jack and roll; this could cause injury or death.

4. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
5. Remove the tyre and wheel assemblies. Refer to Tyre and Wheel Removal and Installation .
6. Inspect the brake system for leaks and visual damage. Refer to Symptoms - Hydraulic Brakes . Repair or replace components as necessary.
7. Lower the vehicle to allow for entry and exit while bleeding the brake corners and other components.
8. Connect a battery charger with 20 amp output to the 12V battery. The battery charger must remain connected and maintain 12V 20 amp for the entire automated bleed procedure. Refer to Battery Charging .
9. Install a scan tool to the vehicle.

Note: The power button must remain ON during this entire procedure.

10. Place the power button in the ON position.

Note: Do not pressurise the pressure bleeder CH-29532-A Brake Pressure Bleeder , and thereby the master cylinder reservoir, until instructed to do so by the scan tool.

11. Using the scan tool, perform the following steps:

11.1.

Select Diagnostics

11.2.

Select the appropriate vehicle information

11.3.

Select Chassis

11.4.

Select Electronic Brake Control Module (EBCM)

11.5.

Select Special Functions

11.6.

Select Automated Bleed

12. Press Start to begin the automated bleed procedure. Ensure the CH-29532-A Brake Pressure Bleeder has not yet been installed to the vehicle.

The travel and pressure sensors are being calibrated and learned by the EBCM during this step.

13. Press Start to continue.

Note: Approximately 2.5-3.0 L (2.6-3.2 qt) of brake fluid will be used throughout this procedure. Ensure there is an adequate supply of brake fluid in the CH-29532-A Brake Pressure Bleeder .

14. Inspect the fluid level in the CH-29532-A Brake Pressure Bleeder . Clean the outside of the CH-29532-A Brake Pressure Bleeder and add GM approved or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container, as necessary.
15. Clean the outside of the master cylinder reservoir on and around the reservoir cap prior to removing the cap and diaphragm.

Note: Do not pressurise the CH-29532-A Brake Pressure Bleeder and thereby the master cylinder reservoir until instructed to do so by the scan tool.

16. Install the CH-35589-A Brake Bleeder Adapter and the CH-29532-A Brake Pressure Bleeder to the vehicle.

Note: Ensure a MINIMUM of 200 kPa (30 psi) of pressure is MAINTAINED in the CH-29532-A Brake Pressure Bleeder throughout this procedure, except as instructed.

17. Set the pressure regulator of the CH-29532-A Brake Pressure Bleeder to 207 to 414 kPa (30 to 60 psi).
18. Open the CH-29532-A Brake Pressure Bleeder fluid tank valve to allow pressurised brake fluid to enter the brake system.
19. Wait approximately 30 seconds, then inspect the entire hydraulic brake system to ensure there are no existing external brake fluid leaks.
20. Secure bleeder hoses to all 4 brake calliper bleeder valves.
21. Bleed each of the 4 brake corners using the CH-29532-A Brake Pressure Bleeder in the following sequence. Ensure the brake fluid is clear and free of air bubbles at each corner.

21.1.

Left front

21.2.

Right front

21.3.

Left rear

21.4.

Right rear

22. Ensure each of the 4 brake calliper bleeder valves are tightened securely.
23. Press Start to begin the system automated bleed steps.

Follow all instructions on the scan tool. Only apply the brake pedal when instructed to do so by the scan tool.

24. When instructed, firmly apply and release the brake pedal using smooth, consistent full brake pedal strokes.

The brake pedal will go fully to the floor with some pedal feedback felt. The master cylinder reservoir supply circuit is being flushed through these steps.

25. Continue the brake applications until instructed by the scan tool.

The scan tool will instruct to perform 10 brake applies.

26. When instructed by the scan tool, stop performing the brake applications and press Enter.
27. When instructed by the scan tool, press Start to continue.

Note: The hydraulic brake system will be under high pressure during the next bleed sequence. Ensure the bleeder hose is maintained securely to the bleeder valve, and open the bleeder valve slowly.

28. Following the instructions on the scan tool, open the right rear (RR) brake calliper bleeder valve.
29. With the bleeder valve open and the bleeder hose maintained firmly in place, press Start to begin the bleeding process.

This process will run in a 30-second cycle. The pump and HPA circuits are being flushed during these steps.

30. Press Enter when instructed to repeat the bleeding process 3 more times on the scan tool.
31. Press Enter when instructed at the end of the 4th bleeding process.
32. Ensure the RR brake calliper bleeder valve is tightened securely.
33. Following the instructions on the scan tool, open the left rear (LR) brake calliper bleeder valve.
34. With the bleeder valve open and the bleeder hose maintained firmly in place, press Start to begin the bleeding process.
35. Press Enter when instructed to repeat the bleeding process 3 more times on the scan tool.
36. Press Enter when instructed at the end of the 4th bleeding process.
37. Ensure the LR brake calliper bleeder valve is tightened securely.
38. Reduce the charge in the air tank of the CH-29532-A Brake Pressure Bleeder to 0 kPa (0 psi).
39. Press Start to continue.

This sequence will run in a 20-second cycle. The brake pedal simulator circuit is being flushed through this step.

40. Press Enter when instructed to repeat the bleeding process 5 more times on the scan tool.
41. Set the pressure regulator of the CH-29532-A Brake Pressure Bleeder to 207 to 414 kPa (30 to 60 psi).
42. Press Enter to continue.

This sequence will run in a 120-second cycle. The boost side of the secondary master cylinder is being flushed through this step.

43. Open the right rear (RR) brake calliper bleeder valve.
44. Press Enter when instructed to repeat the bleeding process 1 more time on the scan tool.
45. Press Enter to continue.
46. Following the instructions on the scan tool, press Start to begin the next bleed sequence.
47. Open the right rear (RR) brake calliper bleeder valve.

Ensure the RR bleeder valve is fully bled and securely tightened before the 60-second cycle is completed. Do not leave the bleeder valve open for longer than 60-seconds.

48. If the RR bleeder valve was not fully bled within the 60-second cycle time, press Start to repeat Step 46 until the brake fluid is clear of any air.
49. Press Enter to continue.
50. Following the instructions on the scan tool, press Start to begin the next bleed sequence.
51. Open the left rear (LR) brake calliper bleeder valve.

Ensure the LR bleeder valve is fully bled and securely tightened before the 60-second cycle is completed. Do not leave the bleeder valve open for longer than 60-seconds.

52. If the RR bleeder valve was not fully bled within the 60-second cycle time, press Start to repeat Step 50 until the brake fluid is clear of any air.
53. Press Enter to continue.
54. Secure bleeder hoses to all 4 brake calliper bleeder valves.
55. Bleed each of the 4 brake corners using the CH-29532-A Brake Pressure Bleeder , in the following sequence. Ensure the brake fluid is clear and free of air bubbles at each corner.

55.1.

Left front

55.2.

Right front

55.3.

Left rear

55.4.

Right rear

56. Ensure each of the 4 brake calliper bleeder valves are tightened securely.
57. Press Enter to continue.
58. Remove the CH-35589-A Brake Bleeder Adapter and the CH-29532-A Brake Pressure Bleeder from the vehicle.

Note: The system is active and pressurised, therefore the brake fluid level in the master cylinder reservoir cannot be allowed to be higher than the MAX mark of the operating range.

59. Ensure the master cylinder reservoir is filled no higher than the MAX operating range line. Add or remove brake fluid as necessary. Refer to Master Cylinder Reservoir Filling .
60. Start the engine.
61. Press Start to continue the final sequence.

The pump and the HPA circuits are being flushed, and the boost valve is being calibrated and learned by the EBCM through this step.

62. Continue to follow the instructions on the scan tool.
63. Allow the engine to idle for 1 minute to allow the system to recalibrate.
64. Place the power button in the OFF position, then place the power button in the ON position.
65. Clear any DTCs from the EBCM.
66. The brake control modulator is an OBDII compliant module. As such, brake related DTCs may be stored in the powertrain control modules. After addressing any other stored DTCs, clear any brake related DTCs stored in the powertrain control modules.
67. Place the power button in the OFF position, without applying the brake pedal.
68. Allow the vehicle to remain OFF for at least 1 minute before applying the brake pedal or performing a test drive.

This waiting period is essential to complete the sensor and boost valve calibration and EBCM learn processes, and to allow the HPA to depressurise to allow for a deactivated system pedal feel check.

69. Remove the scan tool from the vehicle.
70. Before activating the power button, firmly apply the brake pedal several times.

Observe the brake pedal feel.

71. If the brake pedal feels spongy, perform the following:

71.1.

Repeat the base hydraulic brake system bleeding procedure. Refer to Hydraulic Brake System Bleeding : Pressure .

71.2.

If the brake pedal feel is now firm, repeat the automated bleeding procedure.

71.3.

If the brake pedal stills feels spongy after repeating the base hydraulic brake system bleeding procedure, inspect the brake system for external leaks. Refer to Brake System External Leak Inspection .

72. If the brake pedal stills feels spongy, an if no external brake fluid leaks are found, inspect the brake system for internal leaks and inspect the brake pedal travel. Refer to Brake System Internal Leak Test and Brake Pedal Travel Measurement and Inspection .
73. If internal leaks are found, replace the master cylinder. Refer to Master Cylinder Replacement .
74. If the brake pedal travel exceeds specification and there is no damage to the pedal system or pushrod, replace the master cylinder. Refer to Master Cylinder Replacement .
75. Place the power button in the ON position.

Observe if the brake system warning lamp remains illuminated.

76. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be driven until the brake system is diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes .
77. Firmly apply the brake pedal several times.

Observe the brake pedal feel.

78. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake pedal is obtained.
79. Drive the vehicle to a speed above 13 km/h (8 mph) to allow ABS initialisation to occur.

Observe the brake pedal feel.

80. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake pedal is obtained.