My wife hit the brakes hard to avoid a collision and her GS shut off. Took it to dealer and they said the did that to the loaner and said its a normal traits of the car. Just want to see if anyone exp this and is this really normal?

NOT normal and outright dangerous! When the car shuts off you lose power steering, assisted braking, ABS, VSC, and possibly other safety features.

I have done a panic braking once in my GS from 50+ to zero and it did not shut off.

You may not lose steering as it's electric.I didn't seem to lose power steering when I stalled in the wife's CX but like you stated still dangerous.

I had to panic break last week when an a-hole cut me off and stopped infront of me (i think it was an insurance scammer - there are many here and target nicer cars) and mine did not shut off.

Check this thread.

https://www.clublexus.com/forums/ls4...he-brakes.html

That's actually interesting. I may have to go to an empty parking lot and test out the electric steering when the car dies. Will the car shut off if you hit the Start button while driving? Hmm

When I had my 2013, I had to do an emergency braking to avoiding the car in front of me that stopped suddenly due to his late response to the standstill traffic. Brakes performed wonderfully and did not experience car shutting off. That's weird and can be potentially dangerous if you panic brake and don't need to stop completely and the car shuts off on the freeway. See if they will take you out with the loaner to try and recreate it. If they refuse to fix it, I would get a second opinion from another dealer.

I think the steering was still there with power.
I was back up a sloped driveway on ice and wheels spun half way up and the CX stalled.Rolled down the hilly driveway and the steering seemed to be power but I was moving when turning at the bottom of the driveway.

I have never heard of this and not sure why Lexus would say thats normal. Car shutting off while avoiding collision wouldn't make sense, did you have PCS on the car or lane departure.

Carburetor engines used to stall very often after a hard stop, but that was often caused by the fuel sloshing out of the fuel bowl...and re-starting the engine could take a few attempts before successful. It really doesn't surprise me too much that a late model car engine may stall after a hard stop, especially if the drive wheels locked-up because that event would likely confuse the engine's computer in regards to fuel delivery, ignition timing, variable cam timing, etc. and it may just shutdown the engine in such instances.

When I first got my GS I came to a screeching stop on the highway. Definitely the hardest braking I have ever done. My GS did not shut off.

Wow, that is crazy and a first for me. Never heard of such a thing in any car ever. Be on top of this, and get this problem taken care of right away because there might not be a next time if a 18 wheeler is in your rear view mirror and your cut shuts off. And hearing about crappy Lexus dealers enrages me. Of course, bring it to the dealers attention, however if they dont offer to help, call Lexus Headquarters and file a complaint, also call the BBB and file a negative claim against the dealer corporation. Then, they'll lick your boots. Ive been through this with Keyes Lexus. They outright disrespected me, so i called Lexus HQ and the BBB and now they are puddy in my hands. I get VIP treatment. Its over $50,000 car, there is 0 excuse for such conduct by the dealer.

It's very common!

Google Search: Engine Stalls After Hard Braking

I use my engine brake to aid my brakes when braking hard. I don't know how hard u guys brake but I've done some moderately hard braking and never had my engine shut off.

How about with (locked-up tires) maximum brake pedal force ('through-the-floorboard' so to speak) as-if you are going to hit a brick wall, and coming to a complete stop? Do you think such an event may confuse the engine with an abrupt stopping of the transmission's torque converter that just a split second prior was happily locked-up to the engine turning [say] 2,500 rpm? Do you think such an event may confuse the ECU that sends the engine its parameters for fuel delivery, ignition timing, cam timing, etc., etc.? I can easily see how an engine could stall due to such an event...