Skip the auto shop - Our mechanics make house calls

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

asked by on

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)?

A: Hello. This can be a dangerous issue and do...

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Removing heater core

Hello. If I understand the situation correctly, you are talking about the metal tubes that run from the inside of the vehicle, through the firewall, which are the supply and return lines for the coolant to the heater core. ...

Q: Car jerking at 25 MPH

Hello. From what you describe, it sound like your transmission is slipping. The first thing to check would be the transmission fluid level. If the level is low, it will need to be topped up to the full level. If...

Q: Car won't start

Hi there. Have the battery tested even though it may be new; there is a chance that it could be defective and that's why it comes with a warranty. If the battery has tested good then it sounds like it...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.