CUSTOMER CONCERN Brake warning instructs the driver not to drive; the brake pedal vibrates and the hydraulic pump runs during application, with U0129 and C1800 stored. CAUSE Confirmed failed Electronic Stability Control module causing loss of brake-system communication and an Active Hydraulic Booster CAN timeout. CORRECTION Remove and replace the Electronic Stability Control module, clear DTCs, and verify brake-assist, CAN communication, and warning-lamp operation.