bratochka9060

Hello everyone!
Did`t find similar problem in the web so i am hoping for more with us in the forum! My car is 2010 E61 530d M57 xdrive 235hp ZF6hp28, stock, 250 000km, DPF cleaned, EGR in place, Transfer case, transmission, all fluids, filters serviced regurally by myself or in service if needed any special equpment. So the issue is that when driving downhill at around 60mph/90~100km/h with light throttle or no trottle at all, i fill like the car is stopping for a fraktion of second, like i am pushing the brakes for a moment, for example if driving down hill for 30 seconds, it will apear 3 to 4 times for around 0,5s every 6-7 seconds, but not constantly, i mean some times there is no problem, some times she is doing it. And she is doing it in 5th gear only. I dont see or feel any missfire in the engine or RPM change. I have Bimmerlink app and i am constantly checking Actual/Expected parameters like Manifold pressure, Air mass, Fuel pressure, back pressure, EGR, TC Swirl flaps(new reinforsed from PMG TECHNIK) actuators %, and during everyday driving all seems good. But it`s hard to replicate this behaviour and to monitor the data at the same time, because she is not doing it every time. Adaptation values of the transmission are ok for now and i dont feel issues with it: A-300 B-335 C-400 D+4 E-88/ TimeA+16,B0,C-17, D0,E+17. I dont have any error massages. I will apriciate if someone can give me some clue what to search or met with simillar issue.
Thank you!

spectre6000

Is it raining when this happens?

bratochka9060

No, it happens in any condition. Just when it is raining typically there is more traffic and i can't drive at 60mph.

spectre6000

I know that the brakes will pulse lightly when it's raining to keep water off the rotors. It uses the RLS to tell when it's raining. I don't think it's as fast as you're experiencing, and it's not supposed to be noticeable, but something is misbehaving, so it's not impossible. Still, doesn't sound like what you're experiencing. Too many strikes in the against column. Just figured I'd let you know my thinking re: why I asked about rain so you don't end up going down any rabbit holes.

bratochka9060

Lol, first time i hear about that feature. But i have met that behaviour mainly in dry weather and yes it is noticeable, like i am pushing the brakes very quick and for short amount of time. And ok, i did not said it correctly in the first post, but i have 1 error from when i bought the car(minor for me), i guess when previous owner changed the front glass and i think it would not change the driving dynamics of the car- 9CC5 LM(RLS) error and as i see it is common error.... Hmmm

spectre6000

Well... You could maybe try fixing that error. If it's the rotor cleaning feature run amok, I think it's still somewhat amok, but it might narrow down your scope. Replace and reset the sensor, or if your windshield is in bad shape, replace your windshield and maybe it'll clear up. Then it might only do the brake pulsing thing when it's actually raining, and you might at least be able to narrow down your gremlin hunt.

Zamme92

Did you solve the problem?

I have the same issue with my 2010 E61 520i.

Driving on good road with cruise control. Any speed below 90kmh. The car brakes for a second and the economy needle goes high, and then comes back down again.

bratochka9060

Not yet, but it is still appearing from time to time. Just now i don't have time to dive deep into troubleshooting.
Interesting that you're seeing also fuel consumption change, which i don't get.
I am planning a service of the transmission (mechatronic solenoids, sealings, etc), transfer case bearings/ sealings, and a bunch of other things for preventative maintenance, as soon when i get free time(planning to do them by myself).
I will update on that!

Zamme92

Oh okay
Im driving a Manual. And it happens every 1-2 minutes. No fault codes on the issue.
I only have this problem when i cruise and the consumption is low. (only driver).

Same problem for a few years now, it stays the same, not getting worse.

bratochka9060

I read in some e9x forums, that it might appear if some of the brake pads get stuck when this break drying activates(part of the DTC). For example if there is big or uneven wear on the brake rotors.