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Cruise control desync bug

Discussion in 'Model S: User Interface' started by SG57, Nov 1, 2016.

  1. SG57

    SG57 Vendor

    Jul 24, 2016
    Spokane Valley, WA
    Not sure if this has been reported before or where to report firmware bugs, but I can confirm in 7.0 and 8.0 firmware a cruise control bug exists.

    The cruise control numerical display and the actual set cruise control value can be desync'd (off by 1) if you turn on cruise control and just before the car reaches the set cruise control speed displayed, you adjust your cruise control speed up or down by 1 while pulling your foot off the accelerator.

    This causes the cruise control display to not update, but the actual set cruise control speed does.

    I'm able to reproduce the bug pretty often if I explicitly try for it.

    Reproduction steps:
    1. Get up to 30 mph with your foot on the accelerator
    2. Turn on cruise control set to 40 mph
    3. Keep your foot the same on the accelerator as your speed climbs to 40
    4. At 39 mph, quickly pull your foot off the accelerator and reduce the cruise control speed by 1 at the same time.
    The desired behavior should be the cruise control display reduces to 39 from 40, and the actual set cruise control value is also at 39 evidence by the speed the car is maintaining.

    Some times though, this bug happens where the cruise control display won't change from 40 to 39, it'll stay at 40 meanwhile the set cruise control speed value does decrease to 39, again evidence by the speed the car is maintaining. This effectively desyncs the cruise control displayed from the actual cruise control speed value which is kinda scary.

    If you then adjust your cruise control speed when the bug is present, it corrects itself either by the cruise control display jumping down by 2, or the speed of the car increases by 1 while the cruise control display doesn't change.

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