Rolling Brake Test

Park Brake Module (PBM) has a function for rolling brake test. Rolling brake test is used to check the function of the electrically operated parking brake, e. g., during the annual vehicle inspection.

The following conditions must be fulfilled for 3 seconds before the test and remain during the test for Park Brake Module (PBM) to allow rolling brake test:

• Speed front wheel: 0 km/h.
• Speed rear wheel: 2 - 8 km/h.
• Ignition on/engine running.
• No trouble codes related to switch parking brake, electric motor in brake calipers, or speed signal from Brake control module (BCM).

Remarks 

If conditions for rolling brake test are not met when switch parking brake is activated, then Park Brake Module (PBM) will perform normal application of the parking brake.

There are two different ways to activate rolling brake test: 

• Activate (hold in) switch parking brake.  When switch parking brake is activated then Park Brake Module (PBM) will activate the electric motor in the brake calipers (6/146-147), which presses on the brake pads until minimum required brake force is reached. Then the brake force increases automatically every third second in four steps. Increase of the brake force occurs in steps for a total of approx. 10 seconds.
• Activate (press in) switch parking brake repeatedly.  Activate (press in) switch parking brake once. When switch parking brake is activated then Park Brake Module (PBM) will activate the electric motor in the brake calipers (6/146-147), which presses on the brake pads until minimum required brake force is reached. At repeated activation of switch parking brake, the brake force increases in four steps.