Bug in "dumb" cruise control

[irelandm]

I've owned my M3 LR AWD now for over a year and love it, but I've finally worked out a strange (minor but potentially unsafe) bug with the non-AP cruise control. I've been able to replicate this behaviour several times now.

When I am travelling up a hill (around 5% incline) at around 50-60 km/h (haven't tested at higher speeds), and I engage cruise control, the indicator on the screen shows that it has engaged at that speed, but when I release the accelerator, the cruise doesn't "grab", so I have to keep my foot on the accelerator for the entire length of the hill. When the incline tapers off to a more level road, cruise then takes over. There's no "push-button" method of cancelling the cruise that I'm aware of, other than tapping the brake.

It's annoying mostly, but carries a potential risk. For instance, if the hill was long enough that I had forgotten CC was engaged since I'm still pedal driving, it may suddenly accelerate to the established CC speed. Or if my pedal driving speed had dropped by the time I reached the crown of the hill, it again will accelerate unexpectedly once the road levels off.

Is say this is a bug, not a feature. In those instances, it would be better if the Cruise Control just didn't engage at all, putting a notification on-screen.

I searched the forum but couldn't find anyone else mentioning this issue.

 

[Elbro]

To cancel the cruise control lift up on the right stock. That will cancel all AP functions including cruise.

 

[gecko10x]

Someone else!!

I posted this thread a couple weeks ago, but didn't get any response.

I think this has finally been fixed on version 2019.40.50.7, but I'm not 100% sure, as I haven't been doing anything but going back and forth to work. What version are you on?

 

[Stach]

I've had my TM3 for about 9 months and I never experienced this issue, Until 2019.40.50.7, so I was guessing that it was a bug with this version. It's only happened twice to me, and caught me very much by surprise, while I was trying to set it at 60mph (almost 100kph). Since it's only happened twice, I hadn't tried to figure out why it happened, but the hill theory is interesting and like I said, I was guessing it started on 2019.40.50.7.

 

[irelandm]

Glad to hear this isn't just my car! Also, I'd guess a fix will happen eventually.

Mine is on ver 2019.40.50.7

 

[OCR1]

I’m on 50.7 and I just drove over 1,000 miles this weekend using the non-AP cruise control and did not notice any of these issues. We climbed quite a few hills too.

 

[irelandm]

I’m on 50.7 and I just drove over 1,000 miles this weekend using the non-AP cruise control and did not notice any of these issues. We climbed quite a few hills too.

It's *only* while trying to engage CC on a steep incline. It works all other cases just fine.

Edit: just to be clear, if I turn on CC while driving on a level road, then encounter a steep incline, CC maintains just fine.

 

[MarkBrokeIt]

What is "non AP cruise control"?

 

[OCR1]

What is "non AP cruise control"?

Prior to late Q1 2019 Model 3's did not include autopilot in the base price. It was a $3,000 add on feature. If you did not buy it, you just have basic non-traffic aware cruise control (no auto steer). It's like cruise control from the 1990's.

 

[irelandm]

What is "non AP cruise control"?

No Autopilot, not adaptive, (so no steering, no slowing down for slow cars or anything), just "dumb" cruise control.

 

[AlanSubie4Life]

I searched the forum but couldn't find anyone else mentioning this issue.

I'd use the voice command to file a bug report whenever this happens next time. I could see this being a relatively uncommon situation that they may not have caught during regression testing for whatever reason (since there aren't many vehicles out there with dumb cruise control).

As already mentioned, push up on the stalk to cancel cruise control. But that's not a solution to this problem.

 

[ZOMGVTEK]

I kinda miss the days where you could feel the cruise control pull the pedal out from under your foot. I think it’s kinda strange if you snap off the throttle with the cruise on, the car acts like normal and will apply regen until it slowly feeds power in to maintain speed.

I’d assume they have a power limit set on the cruise, and if you’re above that it just won’t engage. This is likely more of a lazy approach to the implementation. Basic cruise on Model 3 is remarkably crude. It should probably be a bit smoother, and radar assisted as a default.

 

[irelandm]

I’d assume they have a power limit set on the cruise, and if you’re above that it just won’t engage.

That would be nice, if it actually just failed to engage, but it "turns on" without taking over until the incline decreases, at which point it begins to accelerate to the prescribed speed even if you've slowed. It becomes obviously dangerous if someone merges into your lane at a slower speed, then you crest the hill and you nearly rear-end them due to unexpected acceleration.

 

[ZOMGVTEK]

Oh wow, that’s probably not intended. That’s a problem.

 

[vnxs]

Just chiming in to say that I've experienced this too on a steep hill, though it was several months (and versions) ago. As OP described, the issue occurred when engaging cruise control while driving uphill around 40 mph. Although the set speed was circled in black, indicating cruise control engagement, releasing the accelerator resulted in deceleration below the set speed.

 

[gecko10x]

I think this has finally been fixed on version 2019.40.50.7, but I'm not 100% sure, as I haven't been doing anything but going back and forth to work. What version are you on?

Doh. I can now confirm, as others noted, this is still present on version 2019.40.50.7.

 

[640k]

Prior to late Q1 2019 Model 3's did not include autopilot in the base price. It was a $3,000 add on feature. If you did not buy it, you just have basic non-traffic aware cruise control (no auto steer). It's like cruise control from the 1990's.

No Autopilot, not adaptive, (so no steering, no slowing down for slow cars or anything), just "dumb" cruise control.

TBF - people have actually requested the ability to turn on their AP-assisted (TACC?) CC. When I'm on the highway, not staying at speed has got me stuck in situations where I cannot pass. Had the CC remained consistent, I would have been able to pass. So now I have to be aware of when the vehicle will decelerate. This isn't normally an issue, but if someone is going significantly slower than surrounding traffic, the amount of deceleration can be a problem.

 

[Skookum Chuck]

+1 on the lack of clear AP engagement on hills. 2018 LRAWD3...Bug affecting safety, more important to resolve in an update than adding more video games.

 

[Rogue Synapse]

TBF - people have actually requested the ability to turn on their AP-assisted (TACC?) CC. When I'm on the highway, not staying at speed has got me stuck in situations where I cannot pass. Had the CC remained consistent, I would have been able to pass. So now I have to be aware of when the vehicle will decelerate. This isn't normally an issue, but if someone is going significantly slower than surrounding traffic, the amount of deceleration can be a problem.

You mean turn off the TACC in favor of "dumb" CC, right?

 

[irelandm]

TBF - people have actually requested the ability to turn on {I assume on or off} AP-assisted (TACC?) CC.

I agree. When I had the AP trial (twice), I found the TACC was annoying in 2 ways. First, when the speed is based on GPS and it's wrong (too fast in residential, too slow on secondary highway), and in the case you describe whereby a slow vehicle causes your own speed to drop at an inopportune moment. Its behaviour when changing lanes in that situation is also not ideal in my opinion - twice I encountered the vehicle accelerating to overtake _beyond the speed limit_. This is illegal in my neck of the woods (although we all do it LOL). It annoyed me that the computer assumed I wanted to overtake aggressively. Let my own foot do that, thankyouverymuch.