Cruise Control Problem?

[ScottM]

(Couldn't find this in a search of the forum, happy to be redirected if it's already covered somewhere...)

I have a strange problem with the cruise control on my E89.

Here's what normally happens:
1. 'set' cruise with stalk; dash briefly shows speedo icon with the set speed, and green light moves around speedo dial to position for that speed
2. sometime later, 'cancel' cruise with stalk; green light changes to orange, cruise is now off, continue driving as normal
3. sometime later, 'resume' cruise with stalk (or press 'set' to set new speed): orange light around speedo turns green again, dash briefly shows speedo icon with set speed

There is no gear changing, braking, or appreciable change of speed at any point during this sequence.

But sometimes, the following happens instead. I can go for days without this happening, then it will occur a few times in one journey, then not happen again for days:
1. as above
2. as above
3. when trying to 'resume' or 'set' the orange light stays orange, and the dash shows the speedo icon but with "---" instead of the speed, and the cruise stays turned off

When this happens, none of the cruise operations (set/resume/accelerate/decelerate) do anything. Only two things fix it. Either turning cruise off completely and starting again, or also I've found that if I press the clutch, put the gear lever in neutral then straight back into the same gear, I can then 'resume' the cruise control.

I did wonder if the cruise was objecting to being in too high a gear for the set speed (cf the "change down" icon it sometimes displays), but the above happens at all sorts of different speeds and engine revs.

So, has anyone else experienced this, or anything similar? If so do you know why it happens? Am I doing something wrong, or is it a software bug in the cruise system, etc? Obviously I'll have to ask BMW about the latter, but I thought I'd gather whatever info people have about it first.

Thanks,
Scott

 

[sars]

My cruise is probably on more than it is off, but I have never had that problem or any other tbh, sorry

 

[Wondermike]

What speeds are you going when it happens, your symptoms would happen if you were trying to resume but below the minimum speed threshold?

 

[ScottM]

>> What speeds are you going when it happens, your symptoms would happen if you were trying to resume but below the minimum speed threshold?

Yes, I thought of this and have tried various experiments. Let's say I'm in 5th at 50mph, set cruise, it comes on ok and is perfectly happy at that speed. Then turn cruise off (orange light around speedo), coast for a bit, then use accelerator to return to 50mph, and try to resume cruise. Most times it's fine, sometimes it doesn't work as per original post. I've tried this in various gears at various speeds, same results.

I've now found that changing gear has nothing to do with it; the key action that "resets" the cruise and gets it working again is simply to press and release the clutch.

Note also that completely turning the cruise off and on doesn't fix it, contrary to what I originally thought. Pressing the clutch is the only thing that resets it.

But it sounds like no-one else has experienced this so probably time to talk to Mr BMW. Thanks for suggestions though.

 

[Stafainn]

How accurate is the light on the speedo? I always find that it shows 3mph under the speed that's actually set on the cruise control.

 

[Z_Victor1]

Sounds as if it's faulty....maybe time for a software reflash (?)
If cruise is engaged, when you depress clutch it should disengage...presumably that does happen.
If not, engine would run to limiter.....
But if you're above the min rpm and/or speed for cruise to engage, then it will...if it does not, tis at fault.

 

[ScottM]

For the benefit of anyone else with this problem, software update seems to fix it, viz:

Took car to dealer. They weren't aware of this specific problem, but did say there were several software updates for the cruise control. They didn't say exactly what those updates were for, but they applied them all to the car.

Since then, problem hasn't reappeared (but it was always intermittent so it's hard to be 100% certain).