I have a 2009 IS 250 that accelerated out of control for a couple seconds the other day, and the floor mat was not the cause. It was 100+ degrees that day and I floored the vehicle to merge into traffic. It stuck for a couple seconds and braking did nothing. I took it to the dealer to have it checked out and they blamed it on after market floor mats (of course they did). I refuse to believe that was the cause, especially considering the millions of Toyota and Lexus vehicles with accelerator pedal issues. Anyway, I asked them about the brake override system update mentioned on the Lexus website (press release section) and the service manager said he has never heard of such a thing. I was like wtf? I believe this comes standard on a lot of vehicles nowadays, and dating back to 2010 or so. Has anyone with an IS250 had this software update installed? I'm assuming it's a simple software update. It reduces power to the engine if the accelerator and brake are applied simultaneously. Links to the press releases:

http://pressroom.lexus.com/article_d...rticle_id=1891

http://pressroom.lexus.com/article_d...rticle_id=2391

Without discussing the situation in question or what happened with the acceleration or pedals/mats on your car, does your Lexus have any outstanding recalls? If not, then it already should have the override system. All IS250/IS350 models with all recalls completed will have brake override. The recall was 9LG and involved replacing the accelerator pedal pad, floor mats and installing the brake override system (ECU software update). Look at your vehicle (likely on the underside of the hood) for an authorized modification label, if present it will state that the software update was applied.

On that label it should state the updated part number of the replacement ECU as well as the new calibration ID, it should look something like this:
IS250/4GR-FSE/MT/FR 89661-53C42 35379200
IS250/4GR-FSE/6AT/FR 89661-53C52 35380200
IS250/4GR-FSE/6AT/AWD 89661-53C62 35381200

If you shoot me your VIN, I can see if this recall has been completed on your car.

Jeff

If you have it on "Power", instead of "Normal", - then it's a normal behavior. It goes to 5K+ RPM and stays there for a few seconds, if floored hard enough

Don't think mine has this. It's a 2010.

I mean this

That link didn't work for me. Does the 2010 IS250 have power/normal/snow modes?

reposted image

I see. Thanks. So it is normal for the car to continue accelerating after flooring it when in PWR mode? What benefit does that have?

Exactly what it says. I think it downshifts 2 gears and holds it at that RPM for MAX power.

The RPMs "holding" doesn't make sense to me. You let off the accelerator because you want to stop accelerating and the car decides to continue accelerating? Why on earth would you want it to do that? Doesn't sound like a feature; sounds like a hazard.

Just set it back to "ECT" and see if it's going to do the same. I doubt it will, but who knows...

was your car actually revving and accelerating?

PWR mode will keep your RPM high for few seconds, but it shouldn't accelerate when your foot is off the pedal (unless it's a downhill).

It'll sound like it's still accelerating, but it's not going anywhere.

Yes, if it seats at 5K RPM and you're pushing brake pedal at the same time, - that's how it feels, hard to stop.
That's why you'll have to know when/how to drive on "power" mode. RPM go high fast and go down very slow.