EPB Service Mode
A diagnostic scanner command that retracts the electric parking brake actuators to allow brake pad replacement.
EPB (Electric Parking Brake) Service Mode is a specialized diagnostic software command used to retract the electric caliper motors on vehicles equipped with electronic parking brakes. When the parking brake is set, an electric motor on the back of the caliper drives a threaded spindle forward, mechanically clamping the brake pads against the rotor.
To replace the rear brake pads, the caliper piston must be pushed back into its housing to make room for the new, thicker pads. On traditional calipers, this is done with a manual C-clamp tool; however, on an EPB caliper, attempting to force the piston back without retracting the electric motor will crush and destroy the internal plastic gear drive mechanism. Activating Service Mode runs the electric motor backward, fully retracting the internal spindle.
Once the new pads are installed and the calipers reassembled, the technician must exit Service Mode, which calibrates the parking brake by driving the pistons forward until they touch the pads. If a diagnostic scanner is not available, some vehicles have a manual dashboard button sequence to enter service mode. Failing to perform this calibration can cause the parking brake to malfunction or bind.