10:35 04-09-2025

Start/Stop in modern cars: pros, cons and when to hit A OFF

Almost all modern cars now come with a Start/Stop system. Its job is to switch the engine off during brief halts—at traffic lights or in traffic—to cut fuel use and reduce emissions. On the dash you’ll usually find a button marked with an “A” in a circle or labeled “A OFF.” That’s the control that lets you temporarily disable the feature.

The idea sounds straightforward: the engine shuts off when the car is stationary and restarts the moment you release the brake or press the clutch. In city driving it can indeed deliver up to 10% fuel savings. Yet behind the wheel, smooth, predictable responses often matter more than theoretical gains, so it’s no surprise the system has plenty of detractors.

First, constant starts and stops increase the load on the starter and the battery. These cars do use reinforced components, but their service life still tends to drop. Replacing an AGM or EFB battery, in particular, costs noticeably more than a conventional one. Second, the system doesn’t always behave perfectly: the engine may switch off at an awkward moment—say, when you’re creeping toward a junction—which many drivers find irritating.

Manufacturers offer a way out—the “A OFF” button. Press it, and Start/Stop remains off until you start the car again. Some models can be programmed so the system doesn’t activate automatically, but more often you have to press the button by hand every time.

Opinions among drivers are split. Some say the feature helps cut fuel use and is kinder to the environment. Others insist the savings are merely symbolic, while the cost of a battery or starter wipes out any benefit. Skepticism is strongest among those who spend a lot of time in the city and deal with frequent activations.

Whether to switch Start/Stop off comes down to habit and personal preference. If pressing “A OFF” brings a sense of relief, you’re far from the only driver this technology gets on the nerves of.