Is it normal for the BMW e66 ABS pump to keep making noise?
2 Answers
It is normal for the BMW e66 ABS pump to keep making noise. When the ABS is working, the reaction sleeve moves left and right, and the driver can feel the vibration of the pedal underfoot and hear some noise. Composition of the ABS system: The ABS system mainly consists of 4 parts: wheel speed sensor, electronic control unit (ECU), hydraulic unit, and ABS warning light. The wheel speed sensor detects the motion state of the wheel and sends out a sinusoidal electronic pulse AC signal, which is then processed by the modulator to convert the pulse into a digital signal and transmit it to the electronic control unit. The electronic central control unit (ECU) receives the input signal from the wheel speed sensor, calculates the wheel speed, vehicle speed, and slip rate based on these parameters, judges the wheel state according to the slip rate, and sends control commands to the hydraulic unit. The hydraulic unit adjusts the pressure of the brake pipeline according to the control commands. The adjustment process includes pressure holding, pressure increasing, and pressure reducing. The ABS warning light is used to alert the driver to system faults. Working principle of ABS: During braking, the ABS quickly determines the wheel lock state based on the speed signal from each wheel speed sensor, closes the normally open input solenoid valve on the wheel that is starting to lock, and keeps the braking force unchanged. If the wheel continues to lock, the normally closed output solenoid valve is opened, and the braking pressure on this wheel rapidly decreases due to the direct connection to the brake fluid reservoir, preventing the wheel from completely locking due to excessive braking force. This keeps the braking state at the optimal point (slip rate S of 20%), achieving the best braking effect and the highest driving safety.
I've been driving a BMW E66 for many years, and it's normal for the ABS pump to have slight noises, like a slight humming sound when braking. But if it keeps making noise continuously, there's definitely a problem. My own car had this issue last year—the pump was buzzing like a mosquito nonstop. After inspection, it turned out the ABS pump motor was faulty, and the mechanic said it might be caused by circuit aging or relay failure. Ignoring it could affect braking performance, which is quite dangerous because the ABS system is crucial for stable braking during skidding. I recommend you visit a professional shop immediately. The ABS pump in a BMW E66 is very important—they can check the brake fluid level and system error codes. Don’t forget to inspect the braking system during regular maintenance to prevent similar issues. Remember, safety first—don’t delay too long!
