Bmw x5 e70 2009

[Tiberius73]

We have a BMW X5 E70 from 2009. 120k miles.

It's been pretty fine all the way until last September 2023 when the hand-brake started acting up. The error 6023 keeps coming up. Intermittently. Only this error. We replaced the actuator with a used one and all was good for ~2 months.

Now, we hardly used the parking brake - only when parking on an incline basically so it's not disabling us. Now, January 2024, the error comes on intermittently after an engine start. It's rarely on when unlocking the car but occasionally it is. But it always comes on 2-3 minutes after driving off and then goes off within seconds. Comes back on again and again off within seconds. So the car gongs and before the gong is finished, the warning light is already off. The error is never happening if the car has been driving for a while. Like, never ever.
The issue with the error flashing on/off incl the gong lasts for 3-20 minutes. It seems temperature dependent; when it's colder outside (50F/10C) the intermittent error can re-occur even 10, 15 minutes after setting off. When it's warm (70-75F/20-25C) it'll happen once or twice within ~2-3 mins max. If we park the car even for ~5 minutes, the fault and instant clearing of the fault and gong can happen again.
EDIT: to add that when the warning is off, the parking brake works perfectly.
EDIT: also the dealer has no idea and just wants to swap parts for $2-3k.

It's only error 6023. There are no other errors. We checked the actuator and the wiring, and nothing seems wrong or damaged. We measured the voltages all over the car, and the voltage is 14.1 to 14.4V, even when the error occurs. The battery isn't discharged and sits at 12.4V when the engine is off for a while. We even measured this voltage while the car was locked, powered off. We unlocked the car, saw error 6023 occur and yet the voltage didn't move. Only when starting the engine did the voltage dip, but the error was already set by then anyway.

Now this is the second actuator (a used one though) with the exact same issue. We replaced the last actuator in November and it was behaving the same exact way; error 6023. And only 6023.

Does anyone have any idea why this is happening? I don't mind not having a parking brake (although it would be nice) but the constant gongs when driving are quite irritating...

[zjuyyhu]

I would recommend to get a new aftermarket part (e.g., URO brand) which costs about $400. I replaced it two years ago and this part works like genuine one, very happy with it.