Strange TACC behavior

pedriscoll · Nov 13, 2015

Yesterday on a trip from Indianapolis to South Bend and back the TACC would intermittently slow the car down for no obvious reason. There was not a car close enough in front to cause it. Driving conditions were remarkable for fairly high wind; sustained at 25 mph with gusts into the 40s. This is the first time the TACC system did not perform flawlessly since I took delivery in June. I was not using lane keeping due to poor lane markings on US 31. Has anyone else experienced similar behavior? Today on my normal commute everything worked fine again.

Rockster · Nov 13, 2015

It was doing this to me near Georgetown, TX last weekend, in an area of relatively new highway construction. The car suddenly slowed from its setpoint of 70 mph to 50 or so. There were no other cars within miles. It happened three or four times in an area of a few miles.

I wasn't sure if this was anomalous or somehow tied to the fact that perhaps the nav system didn't think my car was on a real road.

pedriscoll · Nov 13, 2015

It is interesting that during the times it happened the nav system was telling me to take a different route. There is a bypass around Kokomo, IN, that is several years old, but the nav system does not recognize it.

DavidB · Nov 13, 2015

Have you checked how clean is the forward radar and the windshield near the forward camera? Debris blocking portions of the radar sensor might be the cause of unexpected behavior.

mwulff · Nov 13, 2015

I started a thread about this issue here: http://www.teslamotorsclub.com/showthread.php/56365-TACC-with-7-0-unexpected-slowdowns

The fault lies with the tacc and the outdated navigon maps. This is confirmed by Tesla. Read the thread and watch the video for an explanation.

pedriscoll · Nov 13, 2015

Thanks, mwulff. The other interesting thing is that I did turn the nav system off and the problem persisted. I was still on the section of road that had not been updated in the nav system. I hope they fix this soon. It certainly could be a significant safety issue.

garygid · Nov 14, 2015

Apparently you are driving "off-road" according to the dashboard's obsolete map.
It is probably a TACC "safety feature" that Tesla will need to modify.
For now turn off TACC when driving on "new" roads, unknown to the onboard map.

CHG-ON · Nov 14, 2015

How annoying. We have the only car that can completely update itself OTA and we can't get map and nav updates. What the heck?

pedriscoll · Nov 15, 2015

I also find it very strange that the 17" display uses a different database than the actual nav system. The big display clearly shows the road I am on while the nav tells me to turn off. For all it's faults, Apple maps at least can plot the same route accurately.

GoTslaGo · Feb 20, 2016

Interesting. I had some incidents where the TACC slowed the car down on an established road. I noticed was that the car had difficulty with the lane markers (terrible road: light colored surface with black metallic grids and white lines on a bright sunny day--presumably reflective). So at one point the car thought that a truck was merging into my lane and began to slow itself down. Don't see it as a problem with TACC, more an issue with a terrible road. I also have significant difficulty using Autosteer on this road.

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Strange TACC behavior

pedriscoll

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Rockster

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pedriscoll

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DavidB

2010 Roadster Sport || 2013 S85 || 2017 X100D

mwulff

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pedriscoll

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garygid

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CHG-ON

Still in love after all these miles

pedriscoll

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GoTslaGo

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