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Unexpected speed up in Autopilot


May 4, 2016
I have had my Model S accelerate unexpectedly on numerous occasions. My wife has also had the same experiences. The below speed behavior happens consistently on a section of road where the speed limit changes from 65mph to 55mph then to 45mph:

@65, autopilot allowed 70,
@55, it allowed 60,
@45, it allowed 50 for a few hundred yards then tried to accelerate to 57 even though the 45mph speed limit was displayed on the dash - Autopilot canceled by me.

The indicator on the dash shows the cruise control speed is 57 although neither my wife or I set that speed.

On one occasion when going the opposite direction on the same section of road this occurred:
Going into the 45mph zone, AP was engaged, 50mph was attained.
In the 55mph zone, 60mph was attained.
In the 65mph zone, the BRAKES came on. The accelerator was used to override the deceleration and AP was eventually turned off.

Other information:
The speed limit warning setting button was set to 'absolute' 75mph
The speed limit warning setting 'relative' button was de selected although the setting was +12mph.
Could this have any effect on overriding the Autopilot?

Any thoughts on this behavior?

So far Tech support has not responded with an explanation.

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