John Harry

When driving our 2019 A5 Sportback Prestige with cruise control on I find it sometimes unexpectedly brakes hard. It seems to be caused by a car entering the highway on a ramp next to me, or in a curve when it detects a Jersey barrier. I know I can override it by hitting the gas but there's a reaction time delay and each time it happens I expect to get rear-ended. It's not clear to me if this caused by the "traffic jam assist” or “Audi pre sense” or some other function, but it's bad enough that I usually turn off the cruise control.

I know I can turn off pre sense, and that I can set adaptive cruise control distance to 1 (the shortest). All I really want is just plain cruise control. Any thoughts? Thanks in advance.

JohnEnglish

It explains it in the manual but you can turn on cruise control without any of the adaptive features.

John Harry

I was not able to find it in the manual. Could you point me in the right direction? Thanks.

JohnEnglish

Check in the MMI under safety systems. I know in the previous generation you could disable the automatic braking if it detected an object in front of you.

superswiss

If it's only happening while ACC is active, then it's not any of the pre-sense safety system. Those are always active whether you use ACC or not and they would apply the brakes if they think you are on a collision course with something regardless of ACC.

It's most likely ACC mistaking another object as a slower car in your path. There are also assistance settings that cause ACC to automatically slow down for sharp curves, intersections and roundabout. I believe Audi calls it Predictive Efficiency Assistant. You can turn that off.

heymoe

I've been hoping to find a way to toggle the cruse control between adaptive mode and old school set a speed and it keeps you at that speed until you tell it otherwise but no luck.Seems silly that you can buy the car without adaptive cruse which gets you just the old school curse but don't get that option if you get adaptive.

Yoshimura

I don't know if it like with my mom new Honda Civic but if a car enter her lane far ahead, the car brakes with no warning from the anti-collision system. Definitely a feature of her ACC!

superswiss

If ACC is engaged at that time, then yes, it's ACC slowing down. That's my point. With Audi and other makes you can turn off the collision warning systems, but you can't turn off ACC braking if it sees a car ahead. That's kinda the main point of ACC. Without that it would just be regular CC and you can't revert ACC to regular CC in these cars.

Yoshimura

The situation I'm explaining is not the ACC slowing down to adjust its speed to the car ahead. The ACC applies abruptly the brakes because a car far ahead and with a similar speed changes lane!

superswiss

I think we are saying the same. ACC can slow down the car either by letting off the throttle or by applying the brakes if the speed difference is too high for engine braking alone to slow the car down sufficiently. ACC will definitely take measures to slow down the car if another car changes into your lane. That can at times be abrupt, because ACC doesn't see the car coming into your lane until its far enough into it to be picked up by the radar sensor that's pointing forward. Some newer systems also use stereo cameras in the windshield to pick up cars entering one's lane before the radar sensor picks them up and slow down more gradually.