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TACC suddenly not stopping for red lights? Worked fine for 213km...

Dec 10, 2020
52
30
Vancouver BC
Just picked up first Tesla yesterday, 2021 model 3 SR+ (No FSD). Also my very first EV.

I've been really enjoying the car and experimenting with TACC. I love the feature, it stops at red lights, stops in traffic, and accelerates properly. Both days absolutely clear weather.

I drove 217km total from yesterday and today. TACC has worked beautifully. My last trip was 17km, 3/4 highway and 1/4 city. The last 1/4, suddenly TACC wouldn't stop for red lights and had to apply brakes relatively aggressively. I experimented a few more lights with slower approaching speeds + cleaning the windshield of any possible dirt obstruction, and it seems like the car still wants to run red lights.

Pulled over and restarted the car, waited the full 2 minutes for the restart. Still wanting to run through red lights...

I know the manual says TACC is not intended to be used in the city and I also know it says that it may not stop for red lights and to keep your eyes out for any possibility of takeover. I am puzzled because before the last 4km of my last drive, TACC was working so well!

Has this happened to anyone else? Any advise? Is this service appointment worthy?
 

TX_M3P+

Member
Mar 6, 2020
559
393
Austin, TX
Without FSD you cannot enable the feature to stop at atop signs and stop lights. Both auto steer and TACC will not stop for lights unless you are behind another driver that stops for the light. If you are first to the line, then you have to stop the car manually.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
9,490
10,677
Riverside Co. CA
="VeryRealPerson, post: 5224686, member: 151094" I experimented a few more lights with slower approaching speeds + cleaning the windshield of any possible dirt obstruction, and it seems like the car still wants to run red lights.

Pulled over and restarted the car, waited the full 2 minutes for the restart. Still wanting to run through red lights...

I know the manual says TACC is not intended to be used in the city and I also know it says that it may not stop for red lights and to keep your eyes out for any possibility of takeover. I am puzzled because before the last 4km of my last drive, TACC was working so well!

Has this happened to anyone else? Any advise? Is this service appointment worthy?

I am not sure I am reading this correctly.... so let me ask. Are you actually saying:

======================

"I know the manual says my car without FSD wont stop for red lights, but I am puzzled because it wont stop for red lights... should I make a service appointment for this?"

=====================

Cause thats what it reads like, but that cant be right.....
 
Dec 10, 2020
52
30
Vancouver BC
I am not sure I am reading this correctly.... so let me ask. Are you actually saying:

======================

"I know the manual says my car without FSD wont stop for red lights, but I am puzzled because it wont stop for red lights... should I make a service appointment for this?"

=====================

Cause thats what it reads like, but that cant be right.....

Did you modify the post? My original posts reads this:
" I know the manual says TACC is not intended to be used in the city and I also know it says that it may not stop for red lights and to keep your eyes out for any possibility of takeover."

Which is to say that fsd may not stop for red lights, which is just tesla covering their butts if it doesn't stop.

Based on what everyone is saying, I must have gotten fsd for the 23rd somehow (my car says it was updated 7am Dec 24 via teslafi). I know for a fact that on Dec 23 it was stopping for red lights without any cars in front of me.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
9,490
10,677
Riverside Co. CA
Did you modify the post? My original posts reads this:
" I know the manual says TACC is not intended to be used in the city and I also know it says that it may not stop for red lights and to keep your eyes out for any possibility of takeover."

Which is to say that fsd may not stop for red lights, which is just tesla covering their butts if it doesn't stop.

Based on what everyone is saying, I must have gotten fsd for the 23rd somehow (my car says it was updated 7am Dec 24 via teslafi). I know for a fact that on Dec 23 it was stopping for red lights without any cars in front of me.

No, I didnt modify your post. I quoted the part I was reading, and then asked you the question I asked. You said: (bolded emphasis mine but no other changes)

Just picked up first Tesla yesterday, 2021 model 3 SR+ (No FSD). Also my very first EV.

I've been really enjoying the car and experimenting with TACC. I love the feature, it stops at red lights, stops in traffic, and accelerates properly. Both days absolutely clear weather.

I drove 217km total from yesterday and today. TACC has worked beautifully. My last trip was 17km, 3/4 highway and 1/4 city. The last 1/4, suddenly TACC wouldn't stop for red lights and had to apply brakes relatively aggressively. I experimented a few more lights with slower approaching speeds + cleaning the windshield of any possible dirt obstruction, and it seems like the car still wants to run red lights.

Pulled over and restarted the car, waited the full 2 minutes for the restart. Still wanting to run through red lights...

I know the manual says TACC is not intended to be used in the city and I also know it says that it may not stop for red lights and to keep your eyes out for any possibility of takeover. I am puzzled because before the last 4km of my last drive, TACC was working so well!

Has this happened to anyone else? Any advise? Is this service appointment worthy?

So, you say you know that TACC doesnt isnt intended for city use, and that it doesnt stop for red lights, but asked if you should be making a service appointment because it wasnt stopping at red lights.... correct?

It sounded so strange to me that I asked what you actually ment. i
 
Dec 10, 2020
52
30
Vancouver BC
You are right that you are not reading it right at all.

Manual was referencing fsd, I was mistaken yesterday that it was TACC stopping for red lights with no cars in front of me. My car must have updated and fixed the mistaken FSD on the 24th. I didn't purchase FSD so I had no reason to think TACC didn't stop for lights.

My correction is manual says FSD may not stop for red lights.

So yes, if the first few replies all said TACC should stop for red lights, then a service appointment would be warranted no?
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
9,490
10,677
Riverside Co. CA
You are right that you are not reading it right at all.

Manual was referencing fsd, I was mistaken yesterday that it was TACC stopping for red lights with no cars in front of me. My car must have updated and fixed the mistaken FSD on the 24th. I didn't purchase FSD so I had no reason to think TACC didn't stop for lights.

My correction is manual says FSD may not stop for red lights.

So yes, if the first few replies all said TACC should stop for red lights, then a service appointment would be warranted no?


This might help. here is the text from teslas website on the difference between autopilot and fsd. Here is the link for verification:

Autopilot and Full Self-Driving Capability

and here is the relevant text copied, in case you dont want to click the link:

====================================
Autopilot is an advanced driver assistance system that enhances safety and convenience behind the wheel. When used properly, Autopilot reduces your overall workload as a driver. 8 external cameras, a radar, 12 ultrasonic sensors and a powerful onboard computer provide an additional layer of safety to guide you on your journey. Cars built between September 2014 and October 2016 include one camera and less-powerful radar and ultrasonic sensors.

There are two Autopilot packages available for purchase: Autopilot and Full Self-Driving Capability.

Autopilot and Full Self-Driving Capability are intended for use with a fully attentive driver, who has their hands on the wheel and is prepared to take over at any moment. While these features are designed to become more capable over time, the currently enabled features do not make the vehicle autonomous.


Autopilot and Full Self-Driving Capability Features
Autopilot is a suite of driver assistance features that can be purchased before you buy your car or after it’s been delivered, and brings new functionality to your Tesla that makes driving safer and less stressful. Available packages include:

Autopilot
  • Traffic-Aware Cruise Control: Matches the speed of your car to that of the surrounding traffic
  • Autosteer: Assists in steering within a clearly marked lane, and uses traffic-aware cruise control

Full Self-Driving Capability
  • Navigate on Autopilot (Beta): Actively guides your car from a highway’s on-ramp to off-ramp, including suggesting lane changes, navigating interchanges, automatically engaging the turn signal and taking the correct exit
  • Auto Lane Change: Assists in moving to an adjacent lane on the highway when Autosteer is engaged
  • Autopark: Helps automatically parallel or perpendicular park your car, with a single touch
  • Summon: Moves your car in and out of a tight space using the mobile app or key
  • Smart Summon: Your car will navigate more complex environments and parking spaces, maneuvering around objects as necessary to come find you in a parking lot.
  • Traffic and Stop Sign Control (Beta): Identifies stop signs and traffic lights and automatically slows your car to a stop on approach, with your active supervision
  • Upcoming:
    • Autosteer on city streets
=================================

So, you can clearly see that "autopilot" which comes with the car, only has traffic aware cruise control and autosteer. "Traffic and stop sign control" (beta) is only available in FSD.

I obviously cant speak to what your car was doing when you picked it up. Its possible that some form of FSD was enabled. What I can speak to however, is the fact that stopping at red lights (traffic and stop sign control, beta) is not "supposed" to work with plain autopilot, so, no, no service appointment would have been warranted.
 

Kevy Baby

Dis-Member
Aug 11, 2019
1,983
1,967
Brea, CA
I don't get why you think I'm disagreeing
TACC = Traffic Aware Cruise Control. It is one of two elements of AutoPilot (AP), along with AutoSteer and controls the speed of the car. This feature has the ability to bring your car to a full and complete stop if the car in front of you has stopped and will automatically begin moving when the car in front of you begins to move.
  1. The manual clearly states that AP is not designed for use on surface streets
  2. AP has zero direct functionality with red light stopping.
By your own admission, you are new to Tesla ownership and may not be fully aware of the capabilities of the car. Stand-alone red-light stopping capability can only be achieved with Full Self Driving (FSD) capability (even EAP does not have this functionality).

If you have experienced "automatic stopping at red lights", I can only see it happening for one of two reasons:
  • You had TACC engaged and it behaved as stated above (stopping your car because the car in front of you stopped, etc.) or
  • Your car mysteriously had FSD "accidentally" installed for a very brief period of time at the beginning of your ownership.
While the second bullet point is theoretically possible (though I have personally never heard of it happening), the reasonable conclusion is that the first bullet point is most likely what happened.
 
Dec 10, 2020
52
30
Vancouver BC
I'm very much agreeing with everyone that traffic light stopping is an FSD feature.

But I am guaranteeing that it's your second point. I know for a fact it stopped for red lights on the 23rd, especially with the late night driving I did that day. Teslafi shows my car had an update 7am 24th. To my surprise on the 24th red light stopping didn't work, hence the initial post.

How many times do you want to go through the same thing when I'm agreeing lol...
 

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