[sparty]

I think I've encountered this a few times:
1. Running in stop-and-go traffic with ACC active
2. Car in front completely stops and the volt completely stops.
3, Car in front starts moving and doesn't slow or stop
4. I hit "+" on Volt to get Volt moving again
5. Volt accelerates to about 6 MPH and moves about 20-30 feet and just stops for no reason.

Look in the rear view mirror and see the nice man in the Silverado about to plow me over for stopping for no reason, and then I hit "+" again and everything is fine. Be interesting to get a code/reason for why the Volt determined it needed to stop.

The other strange behavior was in the beginning of this same commute, I went to turn ACC on. Kept hitting "set" and nothing it wouldn't come on and take over. Maybe after the 3rd set attempt it finally came on and took over.

Appeared to me ACC was having a bad day - grey and overcast conditions, 50 degrees, no rain or other obstructions, flat road, not curvy or hilly.

 

[Barry]

Any chance any of the sensors were obstructed by dirt, bug splatter, etc?

 

[Loboc]

That happens every once in a while with my ELR in very slow traffic (less than 10mph). If the car in front hesitates slightly, ELR can't figure out what to do, so, it stops again. Since I use the go-pedal to resume ACC, nobody behind me notices. I just press harder.

Don't hit 'set' hit 'res' or the go-pedal (unless this is the initial 'Set'). Set only works above 13mph and may not engage if the gap is too narrow. Resume works from zero (as long as ACC stopped the car) and from 5mph otherwise.

A dirty windshield will cause ACC to be intermittent or refuse to work all together.

 

[knodal]

ACC seems to be hyper-attentive to brake lights ahead, so if the person ahead of you braked, that may have triggered your ACC to stop the car. But it sounds like a problem with your car, since it has happened several times.

You are probably aware that you cannot "set" the ACC unless you are going over about 10 mph.

 

[Nihilator]

I've had this sort of issue in my ELR, too. I thought it was because the car ahead hadn't advanced far enough to warrant my car accelerating consistently. Now I give a little extra time / space before I ask my car to resume following the target car.

--Chris

 

[AE7HF]

I haven't had that problem.. but it likes to come up really fast on stopped cars. Also, twice today it almost made me rear end a Maserati. It's like the radar wasn't picking it up. It was weird. I still don't trust it 100% You have to be paying attention with it.

 

[Qinsp]

Today was my first experience with ACC in any vehicle, but it happened to be a 2017 Volt.

It got a workout. 80 miles at an average speed of 19 mph, all congested freeway.

At first, I saw the hiccups and was pissed. But after experimenting a bit, if the traffic stops and the car stops, I wait for the lead car to move about 10 feet before hitting resume, and leave the distance setting on the middle setting. After that, it stopped literally 100 times or more without an issue with cruise set at 75mph.

It scared the snot out of me for an hour. But eventually I got used to it, and ... arggghhh... I LIKE IT!!! OK, I said it. It made a really nasty rush hour freeway nice and relaxing.

Didn't care much for Lane Keep Assist though. When there is no emergency lane in the #1 lane on a freeway, I'm pretty sure it would hit the K-rail and damage the car.

 

[Kraven]

ACC is pretty nice. I use it with the "near" setting as any larger gap causes other cars to cut in front too often. Definitely need to stay engaged however it really does a nice job in the stop/slow and go freeway traffic scenarios.

Lane Keep Assist is just that, assist. Not anything like Tesla autopilot. LKA in a Volt is turns you into a pinball that hits the side of the lane then swings you to the other side of the lane. I think it was really intended as a safety feature, to give you a nudge letting you know you are drifting, but not as a replacement for the driver steering the car.