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Unable to Access TACC

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Dbitter1

Journeyman Member
Dec 12, 2014
217
14
Chicago, IL
Ok, here's a new one. Driving down the highway for about an hour, turn on TACC. Speed is normal highway-ish, like 65 or 70. Then I shut it off, futz with the radio (don't ask), and go to turn it back on again. Nothing happens.

The stick is dead for on/off, but the rotation still works to set the following distance. (Meaning no error like "Can't use that", "call tesla service", "feed me a sacrifice", etc, no response at all.)

Luckily had a supercharger station a bit up the road, pull in, start charging, and reset both panels from steering wheel. Get some free electricity (Thanks Tesla!) while I use the facilities, and go back to the highway. Driving out onto the feeder road, stick still dead... does not actuate anything (~30 MPH).

Get on the ramp, put the motors to work generating an ungodly amount of acceleration (Thanks Tesla!), merge onto highway.... and poof! TACC works again.

Don't yet have the intestinal fortitude to reset both panels while driving at highway speed... and car was otherwise fine (radio, nav, energy graph all worked normally) so no threat to safety... just confused how the signal could be ignored...?
 
I doubt this is the case, but mentioning it anyways. You didn't accidentally press the stalk in to turn TACC on/off, did you? Remember, with the newer firmware, the stalk light won't turn on, so the only way to tell if TACC is available to set is if the little white triangle is anywhere on your speedo (could be at zero).
 
Or your radar sensors might be dirty? Tesla really needs to allow normal cruise control in addition to TACC. I can't imagine this TACC thing will work very well in snow.

No need to imagine: I can confirm that TACC doesn't work when snow packs into the radar housing, and there's no normal cruise control when TACC is disabled, either.
 
this will be the first real winter with autopilot on the road. I can't imagine Tesla not fixing this with a software update.

Tesla considers this a "feature". The idea is that someone may forget TACC was unavailable and they are in regular cruise, right into the rear end of the car in front of them. So for AP cars, it's TACC or no cruise. Personally, I think there should have been some sort of engagement or something. Like try to set it, get an error stating its unavailable, hit pressing and holding towards you for 3 seconds or whatever would engage regular cruise. But Tesla didn't ask for my opinion. ;)
 
Tesla considers this a "feature". The idea is that someone may forget TACC was unavailable and they are in regular cruise, right into the rear end of the car in front of them. So for AP cars, it's TACC or no cruise. Personally, I think there should have been some sort of engagement or something. Like try to set it, get an error stating its unavailable, hit pressing and holding towards you for 3 seconds or whatever would engage regular cruise. But Tesla didn't ask for my opinion. ;)

Its a UX issue. When it is tracking a car in front, they could show a pretty obvious animation.

Anyway, I wonder how bad it really is, but so far very few autopilot cars saw a real winter last year, mostly in Norway due to timing of the release. This year, we have a lot more cars with autopilot and a worldwide full on winter. I think tesla will get the message and it's a software fixable problem.
 
>I doubt this is the case, but mentioning it anyways. You didn't accidentally press the stalk in to turn TACC on/off, did you?
>Remember, with the newer firmware, the stalk light won't turn on, so the only way to tell if TACC is available to set is if
>the little white triangle is anywhere on your speedo (could be at zero).

Been there :redface:.

Called Tesla (fortunately situated quite near), which called in the car, and kindly instructed me in the workings of the TACC on/off switch.
 
Its a UX issue. When it is tracking a car in front, they could show a pretty obvious animation.

Anyway, I wonder how bad it really is, but so far very few autopilot cars saw a real winter last year, mostly in Norway due to timing of the release. This year, we have a lot more cars with autopilot and a worldwide full on winter. I think tesla will get the message and it's a software fixable problem.

The radar housing gets packed with snow within minutes, so even though the roads may still be clear you'll be driving without cruise control as soon as the snow starts flying.
 
No need to imagine: I can confirm that TACC doesn't work when snow packs into the radar housing, and there's no normal cruise control when TACC is disabled, either.

this will be the first real winter with autopilot on the road. I can't imagine Tesla not fixing this with a software update.

How would software remove snow packed into a radar housing?
 
Could they add a heating element where the radar sensor is?

Mercedes mounts their radar at the top of the grill with a glass cover over it and I think both these features help mitigate snow from interfering with the radar.

Many engineering solutions to the problem, but a hardware only solution means more expense or not being able to apply it to existing cars easily. But seriously, designing cruise for half the year is silly. Tesla should fix this.
 
Update, if anyone cares...

So the situation got a little worse... Next day, went to make a right hand turn, using that signal thingy my wife tells me I should be using more often. Audible simulated relay clicks twice... then stops clicking. Dash still flashing the turn arrow, did not have time to do settings to see car animation safely. Then... 50 feet and a second or two later, it works again. Stupid solar flares.

Day after that... driving along, radio playing... with media on R driver console... notice that time is no longer elapsing on the song clock. Steering wheel functionality for forward/advance... all now do nothing. Reboot both consoles... all is well.

Day after that... Miss Tessie goes in for the last of the NG seat parts, and the SC folks patiently listen to me and promise to run tests... all which come back working fine.

But... got a free charge port replacement (some latch issue?) and it comes with a new firmware upgrade... and haven't seen the problem since. Fingers crossed.

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To those inquiring about radar being dirty... no, that's not it. There was a pretty extensive set of autopilot discussions from me and others as we took our new cars into snowstorms last winter, and we all learned a lot from that. Long story short, the car will whine and complain if the sensors are unreliable/dirty/blocked, and you will get messages to the effect of "TACC not functional" or some other alert that an anomaly has occurred. This is just a stone-cold nothing, like the switch was unplugged.

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Thank you, @ecarfan, for the empathy headache.