I have a 2016 IS350 F-Sport with about 77,000 miles. It has been acting funny for a few weeks....

The problem is when I press the start/stop button. Sometimes, the car fires right up like normal. Other times, it does absolutely nothing and I need to press the button another time. Sometimes, it takes three times. Other times, I push the button and the car seems very slow starting up--the dashboard lights will come on and after a couple second delay, the engine will crank and then everything is fine. The problem is very intermittent.

I have changed the battery in the key fob, but that didn't help. I also tried changing to my other key, and that didn't change anything. I brought the car over to the parts store and had them check my battery. It was less than two years old and was showing marginal on their tests. They gave me a new battery and sent me on my way.

I am wondering whether the issue could be the start/stop button itself. Has anyone had one of those buttons actually fail on them? I have also read that there may be a sensor in the brake pedal that could go, but I don't know how to test for that. I am hoping that this isn't the alternator starting to go.

It's worth noting that the car always cranks like normal--there doesn't seem to be an issue with the starter. It just seems very slow to respond to the start/stop button.

Anyone got any ideas?

 

I have changed the start/stop button and the brake pedal switch. The problem is still there. Anybody got any other ideas?

 

I notice if I press the brake pedal at the same time as pushing the button, sometimes my 2019 IS300 does this. I think it is the car not sensing the brake pedal being depressed before hitting the button. See if that is what you are doing. I notice that when I am in a rush I tend to do that.

 

One question that needs to be asked: does your car have this odd behavior just in only one place, in other words, does it just happen only in your garage or your parking place at work or something like that?