The knocking sound occurred for a couple of months, then the Brake, ABS and VSC lights came on the dash yesterday. The code is 1256. My mechanic can't fit me in to replace the accumulator until next week. The only other symptom since those dash lights came on is that when I first put the car in gear to back out of the garage, the car moves back slightly as though there are no brakes, but just for a second. Then, when I mash the brake pedal, the brakes respond normally. The rest of the trip is completely normal. So my question is, can I drive the car safely just a couple of days for short distances until I can take it in next week for the front end work? He is too busy to take my car until maybe next week. Thanks!
If there are issues with the braking, you should not drive the car. Although the brakes should work without the electronic braking, it will be very stiff and you may not be able to stop easily.
This exact thing happens to me too! Although it's intermittent, I'm scared to park on an incline now. How did you check the code?