Cruise control issue

First thought is one of the systems that disengages it is sending a signal when it's not supposed to... Not sure how many of those systems in a 2010, but first step if I were you is identify all of them, then check/test them

 

By any chance, do the dash warnings also light up if you drive a few minutes without cruise control?

Cruise controls can fail when the brake light switch starts malfunctioning and falsely triggers a disengagement. But I'm not thinking of any particular cruise control failure method that should light up any warning lights. But unrelated failures that light those warnings could then disengage CC.

 

Wondering if any of the early auto pilot features like lane control were built into the the 2010 models? That could trigger it, right? But mostly, yes, something with the braking sensor is probably first place to look, I don't think throttle position changes would trigger it, but I know Gen2 better than Gen 3 Prius....

 

Yes, but only in the top trim level, V, not the II (Two).

 

If the warning lights are lighting up before or without engaging cruise control, then I strongly suspect some other problem is being flagged, and the cruise control problem is just a side effect of that.

You will need to read out the diagnostic codes from the car in order to get better guidance.

 

The most common cause of the cruise disengaging is a sticky brake light switch.

BUT........

Those other symptoms are likely to be caused by a 12 V battery going bad, and that might include the cruise failing too.

Let's hope so......because after that it probably gets complicated AND expensive.