These instructions apply to the MG ZS Mk1 (ZS11) 2017-2021.
For other models, please choose your vehicle here.
Your MG ZS (2017–2021) shuts the engine off at a standstill to save fuel. When you’d rather keep it running — crawling traffic, a hot day, or before under-bonnet work — one button switches it off. The circled-‘A’ symbol on the cluster only reports the system’s state; it’s a normal feature, not a warning.
Before you start
- No tools needed — just the ignition on; the engine can be running or off.
- The ZS has no permanent off, so decide each trip and expect to repeat it.
- For under-bonnet work, switch stop/start off and turn the ignition fully off to rule out an auto-restart.
Turning Stop/Start Off
- Locate the stop/start button — an A inside a circular arrow — on the dash or centre console.
- Press it once; the indicator confirms the system is off and the engine stays running at stops.
On ZS models that route it through the touchscreen, look under Vehicle / Settings for the stop-start (engine auto-stop) toggle. The ZS re-enables stop/start at every ignition cycle, so press the button again at the start of each drive if you don’t want it.
If the Engine Won’t Stop — or Won’t Stay Off
If a press seems to have no effect, or the engine keeps idling when you expect a stop, work through these first:
- Weak or cold 12 V battery. Easily the most common cause — the ZS holds the engine running to protect and charge a tired battery, particularly on short journeys and cold mornings.
- Cabin not yet at temperature. On a very hot or cold day the climate demand blocks stops until the interior settles.
- Cold engine. Straight after a cold start the engine stays running until it warms through.
- Clutch or brake input. In a manual the engine only stops in neutral with the clutch fully up; in an auto the brake must be held firmly and the car fully stopped.
- On a slope, the ZS may skip the stop for stability reasons.
- If a warning symbol stays lit while the system is genuinely disabled, have the 12 V battery load-tested before looking further.
Frequently Asked Questions
How do I turn off auto stop/start on an MG ZS?
Press the circled-‘A’ button on the dash or console once and the indicator confirms the engine will idle at stops rather than cutting out. On cars without the physical button, open the touchscreen Vehicle or Settings menu and switch the stop-start (engine auto-stop) toggle off. Either way the change only applies to the current drive.
Can I disable it permanently?
No — the ZS re-enables stop/start automatically each time you start the car, and there’s no factory option to keep it off for good. The practical approach is to press the button at the start of any journey where you don’t want the engine cutting out, such as heavy traffic or a hot day when you want uninterrupted climate output.
Why didn’t the engine stop today?
A stop only happens when the conditions line up: enough 12 V charge, a warm engine, and a cabin near your set temperature. Low charge, a cold engine, strong heating or cooling demand, or resting on a gradient will all keep the engine running by design. It’s normal protective behaviour rather than a malfunction.
Does stop/start wear out the starter or battery?
Not in normal use — the ZS uses uprated components designed for frequent cycling, and it won’t auto-stop when the battery can’t support a clean restart. As the battery ages, stops naturally become rarer. Fitting the correct replacement battery type when needed keeps the system behaving as intended.
If a stop/start fault shows, it usually points to the 12 V battery — see our ZS battery guide, or look the code up on autodtcs.com.
Independent guide — not affiliated with MG. Always follow your official service manual and safety precautions. Read our full disclaimer.