[chris_ss]

I've noticed on the two occasions I've taken my m550 on a road trip that when on a straight treeless road with the cruise set, it will throw an error after an hour or so about driver assistance system malfunction and disable cruise. after 20-30 minutes I can turn cruise on again.

after the first time it happened I took it to the dealership, they ran some software updates but the service writer said that all of the bmw's do it when there is a featureless road, as it confuses the CC system, or something to that effect. I asked him if people buy a second bmw after realizing this, he didn't comment

am I supposed to just use my acura when I'm leaving town, or what's going on here?

[Gautam]

Originally Posted by chris_ss

I've noticed on the two occasions I've taken my m550 on a road trip that when on a straight treeless road with the cruise set, it will throw an error after an hour or so about driver assistance system malfunction and disable cruise. after 20-30 minutes I can turn cruise on again.

after the first time it happened I took it to the dealership, they ran some software updates but the service writer said that all of the bmw's do it when there is a featureless road, as it confuses the CC system, or something to that effect. I asked him if people buy a second bmw after realizing this, he didn't comment

am I supposed to just use my acura when I'm leaving town, or what's going on here?

There are a variety of things that could be wrong, but something is likely amiss. Could be as simple as dirt on the sensors, to them needing replacement, or issues with the steering column.

[ezaircon4jc]

Originally Posted by chris_ss

I've noticed on the two occasions I've taken my m550 on a road trip that when on a straight treeless road with the cruise set, it will throw an error after an hour or so about driver assistance system malfunction and disable cruise. after 20-30 minutes I can turn cruise on again.

after the first time it happened I took it to the dealership, they ran some software updates but the service writer said that all of the bmw's do it when there is a featureless road, as it confuses the CC system, or something to that effect. I asked him if people buy a second bmw after realizing this, he didn't comment

am I supposed to just use my acura when I'm leaving town, or what's going on here?

Sounds like a crock to me! Mine worked just fine in west Texas, which is the definition of featureless!

[AP]

Saying all BMWs do that sounds like he is brushing you off
Doesn’t sound right to me
It shouldn’t throw an error
If it disengaged , it would just disengage , red steering wheel and a beep and it would be obvious that’s what the software wanted to do

An idea, would disconnecting the battery for a bit reset the system, would that be worth trying ?

[LogicalApex]

Originally Posted by chris_ss

I've noticed on the two occasions I've taken my m550 on a road trip that when on a straight treeless road with the cruise set, it will throw an error after an hour or so about driver assistance system malfunction and disable cruise. after 20-30 minutes I can turn cruise on again.

after the first time it happened I took it to the dealership, they ran some software updates but the service writer said that all of the bmw's do it when there is a featureless road, as it confuses the CC system, or something to that effect. I asked him if people buy a second bmw after realizing this, he didn't comment

am I supposed to just use my acura when I'm leaving town, or what's going on here?

What’s a “featureless road”?

He’s blowing smoke. I only have my ACC disable itself and warn me with clear notice in iDrive. Like the sensor covered in snow or rain so thick it can’t see.

What MY and features do you have? And do you have another dealer nearby to escape this incompetent one?

[Honolulu]

Cruise can be turned off several ways. for instance brake pedal sensor that's too sensitive, or mis-installed/adjusted too close to the brake pedal. Could be a bad electrical connection, which would be a nightmare to diagnose. You have to observe more closely the exact circumstances of the event that turns it off.

[Spyder3]

For what it's worth, my 2018 540 had an intermittent failure situation with ACC; when engaged it would randomly be disabled and display error messages on the iDrive display. On a longer trip, it failed working about 5 times over a several hour period.

There was no debris, dirt, water or snow involved. Weather was clear. The windshield and radar sensor was clean.

The car was inspected and tested 2-3 times by BMW service center over a few months. There were no failed systems or logged diagnostic errors (e.g., computer, electrical, power).

The fix was to replace the mounting bracket of the radar sensor (under front license plate) and to calibrate alignment of the radar system.

Since then, there have been no more failures. So, the fix involved replacing a maybe bent bracket and/or alignment issues. This cost me about $1K USD, not covered by warranty .

YMMV, it's a complex system.

[chris_ss]

this is the error message that comes up. sensors are clean, car is clean, weather clear, software has been "reinstalled" by dealership.
Car is a 2019 with all the bells and whistles, extended bmw warranty which covered the initial troubleshooting and software reinstall.

I wish it were easier to replicate the issue than driving for an hour

[Spyder3]

Yep, those are the same messages I had too. Dealer service diagnostics did not reveal any issues. Resolved via radar bracket replacement and calibration.

Like you said, the problem is intermittent and may take an hour (or two or three) before occurring. One thing I noticed, most times the failure occurred, I was travelling towards the sunshine. Who knows, maybe the glare exacerbated my car's calibration issue.

If dealer service diagnostics do not reveal any error logs that point to defective equipment, you might need calibration.

But I'm no expert, YMMV.

Originally Posted by chris_ss

this is the error message that comes up. sensors are clean, car is clean, weather clear, software has been "reinstalled" by dealership.
Car is a 2019 with all the bells and whistles, extended bmw warranty which covered the initial troubleshooting and software reinstall.

I wish it were easier to replicate the issue than driving for an hour

[chris_ss]

another road trip without reliable cruise control.
I called the dealership service counter again to discuss, they again stated that it's an issue with the way the roads are crowned in Canada and particularly problematic in the prairies.
They said that it's been a longstanding issue with the cars, and for a period were ordering new inventory without ACC to avoid customer complaints. They are able to reprogram the cruise button to go into regular cruise mode with a long press (like my acura/infiniti/etc) but this requires a approval from BMW Canada. The service consultant said that this issue, to the best of his knowledge, has not been resolved in new models.

again, I'm baffled at how this is something that people tolerate, my only guess is that no one is test driving vehicles in a long straight line and they just assume that a standard feature on a 1986 accord would work properly on a $100k vehicle.

[LogicalApex]

Originally Posted by chris_ss

another road trip without reliable cruise control.
I called the dealership service counter again to discuss, they again stated that it's an issue with the way the roads are crowned in Canada and particularly problematic in the prairies.
They said that it's been a longstanding issue with the cars, and for a period were ordering new inventory without ACC to avoid customer complaints. They are able to reprogram the cruise button to go into regular cruise mode with a long press (like my acura/infiniti/etc) but this requires a approval from BMW Canada. The service consultant said that this issue, to the best of his knowledge, has not been resolved in new models.

again, I'm baffled at how this is something that people tolerate, my only guess is that no one is test driving vehicles in a long straight line and they just assume that a standard feature on a 1986 accord would work properly on a $100k vehicle.

No idea what they are talking about. I never have issues with my 530e when I drive it up to Canada. Which is done frequently in the GTA area.

I think it is radar related as Spyder3 mentioned. Especially since that is the “sensor” the car is warning about.

It could be shifted in its bracket or it could have issues that keep it from being stable. Either way, I’d call the dealership on their BS and push them to replace the sensor and recalibrate.

[admranger]

This will sound silly, but if you feel comfortable doing it, disconnect the negative battery terminal and leave if off for at least 10 minutes. If you are really comfortable when you take off the battery terminal, if it is a “T” bolt (I have never had to mess with an m550 battery) those are stainless steel and the threads can gall with repeated use. Put some copper antisieze on this threads and reinstall. It’s absolutely no fun when a t bolt snaps. Ask me how I know.

[chris_ss]

I had the reprogramming of the cruise control button done today.
I guess that’s as good as it gets.

[chris_ss]

Well f.
The new programming allows the distance button to be long pressed to switch to non-active cruise mode. But when ACC is off (such as when it has errored out) I’m not able to press the distance button because “turn on ACC before using this button”
I like the cappuccino machine and friendly service at my dealership, but why am I buying a car without cruise control?

[Gautam]

Originally Posted by chris_ss

Well f.
The new programming allows the distance button to be long pressed to switch to non-active cruise mode. But when ACC is off (such as when it has errored out) I’m not able to press the distance button because “turn on ACC before using this button”
I like the cappuccino machine and friendly service at my dealership, but why am I buying a car without cruise control?

Your dealer is screwing with you. Their explanation is nonsense and their "fix" isn't going to work because there's likely some faulty hardware in your car that's going to prevent even passive cruise control from working.

I would take it somewhere else.