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Q: Car involuntarily accelerates 2-car lengths 1 out of 100 times

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I purchased a Lexus-certified used hybrid car and it is exhibiting involuntary acceleration. Two to three times out of 20 when I start to brake, my car accelerates slightly on its own. My car has regenerative braking, so I thought that perhaps the slight voluntary acceleration was normal. It is startling when it happens, but I apply hard pressure to the brake and it stops the acceleration. But “every” time I brake, I have to keep focused and aware that it might happen. When it started doing this, I thought I was hitting both pedals at the same time, but I’m sure that I’m not doing that. The dangerous problem is the distance that it accelerates 1 in 100 times when I brake. My car will accelerate “two” car lengths before I can brake. Naturally, when the mechanic at the dealership rode with me, it didn’t happen! I was told to keep a watch on this and they recorded my complaint. This two-car length acceleration only occurs during summer hot months, like now. There has been no change in the frequency. Have you heard of this in other Lexus hybrids and can you advise me how I can get this fixed (before an accident happens)?

Hello. This can be a dangerous issue and does happen on this vehicle. Typically I have repaired this with updating the computers in the vehicle. Some of the time when the degeneration is not working correctly it is because the computer programming has not properly adapted. If the issue does not occur when the dealer takes it for a drive then I would ask them if they would update the computer for you and that should take care of it. If you’d like to get this fixed, consider YourMechanic, as one of our mobile experts can diagnose your acceleration issue and help you fix it accordingly.

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