BMW X3 Service & Repair Manual: Parking brake function check

IMPORTANT: Follow instructions for Brake testing on test stand.

Rear axle on brake test rig:

IMPORTANT: No gear or drive range must be engaged! Selector lever position "Neutral" on automatic transmission vehicles.

Do not press accelerator! Disregard of these instructions will result in the transfer box engaging, forcing the vehicle off the brake test rig!

Drive vehicle onto brake test stand The vehicle utilises a plausibility check (wheel speed comparison) to detect the brake test rig within a few seconds and switches to brake test rig mode.

The parking brake indicator light flashes slowly when brake test stand mode is activated and parking brake actuators are released.

Following indicator lights are permanently on:

• Parking brake
• Brake system
• Dynamic stability control (DSC)
• Antilock Brake System ABS

Actuate parking brake switch = application of brake pads.

The parking brake indicator light flashes quickly when brake test stand mode is activated and parking brake actuators are partially locked.

Actuate parking brake switch = test force 1
Actuate parking brake switch again = test force 2
Actuate parking brake switch again = test force 3

The parking brake is released again when the button is actuated in the Release direction.

The parking brake indicator light is permanently activated when brake test stand mode is not detected and parking brake actuators are fully locked.

Brake test stand mode is automatically terminated when the vehicle is driven off the brake test stand.

All indicator lights go out automatically! Checking brake force differential at wheel:

Apply parking brake until a wheel circumferential force (measured on brake test stand) of min. 1000 N is reached.

Max. permitted brake force differential right/left ≤35 % (referred to greater brake value).