Five Mystery Buttons in Cars — Most Americans Have No Idea What They Do

Let’s start with one of the simplest examples: the third-generation Toyota RAV4. There’s a button next to the automatic gear selector with no labels—on the button or nearby.

It’s actually quite straightforward! This is the Shift Lock button, which allows you to move the shifter into neutral when the engine is off. Using it requires both hands: one to press the button, the other to move the shifter to N.

Another Toyota example: a button tied to the car’s speakers. Those familiar with older Toyotas will recognize “Party Mode.” Pressing it shifts the audio output mostly to the rear speakers and boosts the bass. Open the trunk, and the party’s on.

Back to Toyota again—this time the 2020 Tacoma. The icon suggests an off-road function, but what does MTS mean? It stands for Multi-Terrain Select, a system that adjusts driving modes depending on the surface: small rocks, large rocks, mud, sand, snow… Nearby, the Crawl button engages a slow “crawl” mode, letting you move steadily over rough terrain without touching the accelerator.

This next one is from BMW. Can you guess what it does? The BC button controls the onboard computer, letting drivers cycle through different display modes, either sequentially or in a custom order.

And here’s a real brain-teaser: a button labeled with the chemical formula for water. When do you use it? On the Toyota Mirai hydrogen fuel-cell vehicle, it’s the water drainage button, letting drivers safely release accumulated water from the tank—right onto the road if needed.

We’d love to hear your thoughts in the comments.