These instructions apply to the Ford Fiesta Mk8 (2017-2023).
For other models, please choose your vehicle here.
The Ford Fiesta Mk8 (2017–2023) has Auto Start-Stop, which switches the engine off when you stop to save fuel. If you’d rather keep it running in slow traffic, it’s one button press to turn off — here’s how, and the normal reasons it sometimes won’t stop the engine.
How It Works on the Fiesta
Stop with the car in neutral and your foot off the clutch (manual) or on the brake (automatic) and the engine cuts; dip the clutch or lift the brake and it restarts. It only operates once the engine is warm and the battery is healthy. The mHEV versions restart especially smoothly via the belt starter-generator.
Switching It Off
- With the engine running, press the Auto Start-Stop button — the “A” inside a looping arrow, on the dash near the steering wheel.
- A dash light confirms it’s disabled, and the engine idles normally at a stop.
Switching It Back On
Press the button again, or simply restart the car — Auto Start-Stop returns to on every time you switch the ignition off and on. There’s no factory setting to keep it off.
Why It Sometimes Won’t Stop the Engine
- The engine isn’t warm yet, or the climate system is demanding strong heating/cooling or demist.
- The 12 V battery charge is low — common after short trips or a battery change before the BMS was reset.
- You’re on a slope, the steering is turned, the bonnet’s open, or a seat belt/door is open.
If it stopped working right after a battery change, the Battery Monitoring System may need resetting — see our Fiesta Mk8 battery guide.
Frequently Asked Questions
Does the Fiesta remember if I turn Auto Start-Stop off?
No — it resets to on at every start. There’s no built-in option to keep it off.
Is the constant stopping bad for the engine?
No — the Fiesta’s reinforced starter and EFB/AGM battery are designed for it, and it skips stops when conditions aren’t right.
Why won’t the engine auto-stop?
Most often a cold engine, a low battery, or the climate system demanding the engine.
The engine shut off as I was slowing — is that a fault?
On the mHEV the engine can stop just before you fully stop, as a fuel-saving feature. It restarts the instant you need it.
If a warning light appeared alongside the fault, look up the code on autodtcs.com. To clear a service reminder, see our Fiesta Mk8 service reset guide.
Independent guide — not affiliated with Ford. Always follow your official service manual and safety precautions. Read our full disclaimer.