Yukon 2WD V8-5.3L (2007)
Hydraulic Brake Booster: Procedures
Hydraulic Brake Booster Calibration
Perform the Diagnostic System Check for DTCs prior to using this diagnostic procedure. Refer to Diagnostic System Check - Vehicle. See: Testing and
Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Starting Point - Vehicle
For vehicles under 8600 GVWR, the EBCM calibrates itself to the Brake Booster Vacuum Sensor to learn specific engine vacuum and braking
characteristics of the vehicle.
If the "Power Brake Booster" activates excessively or if excessive effort of the brake pedal is consistently required, HBB calibration may be needed. To
perform the HBB calibration, perform the following steps:
1. Transmission in Park, engine running.
2. With scan tool connected to the vehicle, check for any DTCs. If there are any DTCs current, diagnose and correct DTCs before proceeding.
3. Apply throttle pedal to attain 3000 RPM
4. Release throttle pedal.
5. Apply and hold brake pedal firmly for approximately 1 second, release brake pedal. Perform this step 3 times. The entire sequence of steps 3
through 5 (consisting of one throttle apply and three brake pedal applies) should take place within 7 seconds.
6. With the scan tool, navigate to the "data display" for the EBCM and observe the "HBB Calibration Status" parameter. It should display
"complete/success" If not, repeat HBB Calibration.
