These instructions apply to the Peugeot 308 Mk3 (P5) 2021-Present.
For other models, please choose your vehicle here.
Your Peugeot 308 Mk3 (P5, 2021–present) shuts the engine off at a standstill to save fuel through its Stop & Start system. When you’d rather it stayed running — heavy traffic, a hot day, or before any under-bonnet work — you can switch it off. The ‘A’-in-arrow symbol you see in the i-Cockpit display only reports the system’s state; it’s a normal feature, not a fault, and it’s meant to move between ready and active as conditions change through a drive.
How Stop & Start Works on the 308
Come to rest on the brake and, once its conditions are met, the 308 cuts the engine while the display, climate and audio keep running on the 12 V battery. Release the brake — or dip the clutch in a manual — and the engine restarts almost instantly. A stop is only allowed when the inhibit conditions line up: the battery must hold enough charge, the engine and emissions system need to be warm, the cabin has to be near your chosen temperature, and the car must be genuinely stationary on a manageable gradient. Miss any one and the engine simply keeps idling.
Before You Start
- Switch the ignition on; no tools are needed and the engine can be running or off.
- Decide whether you want Stop & Start off for this drive only or every drive — there’s no permanent off, so plan to repeat it.
- For under-bonnet work, switch Stop & Start off and turn the ignition fully off so the engine can’t auto-restart.
- Know whether your 308 has the physical button or relies on the touchscreen before you set off.
How to Turn Off Stop & Start
- Dashboard button: press the ‘AⓇ’ (Stop & Start OFF) button, usually on the console or near the gear selector — a message confirms it’s off.
- i-Cockpit touchscreen: on cars without the button, open the Driving / Vehicle menu and switch Stop & Start off.
It Comes Back On Each Drive
Like nearly every car with this feature, the 308 re-enables Stop & Start at every restart. There’s no permanent factory off — switch it off again at the start of each journey if you prefer.
Why Switch It Off?
- Engine-bay work — no surprise restart.
- Stop-go traffic — no constant cycling.
- Hot or cold extremes — steadier climate output.
It also won’t stop the engine on its own when the battery is low, the cabin still needs heating/cooling, or the engine is cold — all normal.
If the Engine Won’t Stop — or Won’t Stay Off
If pressing the button does nothing visible, or the engine keeps idling when you expect a stop, check these before suspecting a fault:
- Weak or cold 12 V battery. The 308 will hold the engine running to protect and recharge a tired battery — the single most common reason stops don’t happen, especially on short runs.
- Cabin not yet at temperature. Strong heating or cooling demand vetoes stops until the interior settles.
- Cold engine or emissions system. After a cold start the engine keeps running until it’s up to temperature.
- Brake not held firmly (autos), or the clutch not fully up in neutral (manuals) — the car must be completely stationary.
- Steep gradient — the 308 may skip the stop for stability and restart smoothness.
- You’ve just switched it off — a confirmation message means it’s working, not faulty.
- If a Stop & Start warning stays lit with the system genuinely disabled, have the 12 V battery tested first.
What to Expect After
Once off, the button’s indicator or an on-screen message confirms it, and the engine idles normally at every stop for the rest of the journey. Start the 308 again and Stop & Start re-arms itself, ready to cut the engine when conditions allow — switch it off again if you want it disabled. Nothing carries over between drives, and no warning should remain once the ignition is cycled.
Frequently Asked Questions
How do I turn off Stop & Start on a Peugeot 308?
Press the AⓇ button, or switch it off in the i-Cockpit Driving menu. On cars with the physical button an on-screen message confirms the change; on cars without it, the toggle lives in the Driving or Vehicle section of the touchscreen. Either way it applies only to the current drive, since the system re-arms at the next start.
Can it stay off for good?
No — it re-arms at every restart. Switch it off per drive. There’s no factory menu setting to keep Stop & Start permanently disabled, so the simplest routine is to switch it off at the start of any journey where you don’t want the engine cutting out, such as slow traffic or a hot day when you want steady air-conditioning.
Why did it switch itself back on?
Restarting the car re-enables it automatically. The 308 always begins each journey with Stop & Start ready, regardless of how you left it last time, because it defaults to the fuel-saving setting. This isn’t a fault or a lost setting — simply press the button or use the touchscreen again to switch it off for the new drive.
Why won’t the engine cut sometimes?
Low battery, climate demand or a cold engine keeps it running by design. The 308 only stops when the 12 V battery has enough charge, the engine is warm, and the cabin is close to your set temperature. Sitting on a steep slope or not being fully stationary will also prevent a stop. All of these are normal protective conditions rather than a malfunction.
Does leaving Stop & Start on harm the engine?
No — the 308 is built for it, with a starter and battery designed for frequent cycling and a system that won’t auto-stop unless a clean restart is assured. The usual reason it feels erratic is an ageing 12 V battery, which reduces how often stops are permitted. If stops have become rare, have the battery checked before assuming anything more serious.
Will disabling it hurt fuel economy?
A little — Stop & Start exists to save fuel while idling, so switching it off means the engine burns slightly more when stationary. Over a single drive the difference is small, and many owners accept it for smoother traffic driving or steadier climate control. For open-road journeys, where the car rarely idles anyway, leaving it on or off makes almost no difference.
If a Stop & Start fault light shows, look it up on autodtcs.com — usually a weak 12 V battery. See our 308 battery guide.
Independent guide — not affiliated with Peugeot. Always follow your official service manual and safety precautions. Read our full disclaimer.