Circuit/System Verification
- Ignition - On / Vehicle - In Service Mode
- Perform the scan tool control function: Deactivate Brake Boost System
- Verify there are no leaks in the component/system: Brake System - Refer to: Brake Fluid Loss
- Apply the brake pedal. - More than 2 times.
- Perform the scan tool control function: Activate Brake Boost System
- Ignition/Vehicle - Off - For greater than 10 min
- Ignition - On / Vehicle - In Service Mode - Brake Pedal Not Applied
- Perform the scan tool control function: Brake Hydraulics Test
- If the procedure/test does not pass
Refer to: Hydraulic Brake System Bleeding
- Go to next step: If the procedure/test passes
- If the procedure/test does not pass
- Perform the following steps: - 10 times
- Apply the brake pedal slowly from 0- 40bar
- Hold the pressure constant for at least 10s
- Release the brake pedal slowly
- Wait 30s
- Verify DTC C2A22 is not set.
- If DTC C2A22 is set
Replace the component: A104 Brake Master Cylinder
- Go to next step: If the DTC is not set
- If DTC C2A22 is set
- All OK.
NOTE:
If the Brake Hydraulics Test still fails after performing the Hydraulic Brake System Bleeding at least 3 times, performing the scan tool control function test Brake System Hydraulics Corner Test can be performed to help isolate the concern.