MG All Keys Lost and Key Fob Issues (MG3, MG ZS, MG HS)

An MG key problem falls into one of two camps — and they could hardly be more different. One is a flat fob battery, a cheap fix you can often do yourself; the other is all-keys-lost, where every working key is gone and the car will not start. This guide covers both across the modern SAIC-built range — MG3, MG ZS and ZS EV, and MG HS — so you can tell which situation you are actually in before you spend anything.

First: is it just a flat fob battery?

If your MG’s remote buttons have gone weak, the keyless entry has become unreliable, or the car flashes that it cannot detect the key, the usual cause is a flat coin-cell battery in the fob — not a failed key. MG smart fobs typically take a single CR2032 coin cell (check the number printed on the old cell before buying). Tell-tale signs it is just the battery:

• The remote only works right next to the car.
• A key-battery warning appeared on the dash first.
• Your spare key works fine when the main one does not.

You can still get in and drive on a dead fob. Pull the hidden emergency blade from the smart fob and use it in the driver’s door lock, then hold the fob against the marked spot (usually the start button or a spot on the column) and press start — MG designed the system to read the fob at close range even with a flat battery. If a fresh, correct battery and that trick both fail, the fob itself has likely failed, and that needs a programmed replacement, not just a new cell.

The big one: MG all-keys-lost

Losing your last working MG key is more stressful because it is not obvious who can help — but all-keys-lost is a routine auto-locksmith job. You do not have to recover the car to an MG dealer, and you do not need a new car computer.

It is harder than making a spare because the car trusts nothing, and MG adds a specific hurdle: to code a new key from scratch, the immobiliser requires the vehicle’s security (PIN) code. With dealer-level equipment we obtain and apply that code — the step a general key-cutter cannot do — then register a fresh key. Our MG smart key programming guide explains the coding side in more depth. What an all-keys-lost involves:

• Prove the car is yours: ID and proof of ownership (V5C/logbook) before we generate keys — standard practice and your protection.
• Get into the car: if it is locked, we gain non-destructive entry — no drilling, no broken glass. See our lost-key and lock-out service.
• Cut the blade: the mechanical/emergency blade is cut to your locks.
• Obtain the security code and code a new key: the immobiliser is brought into a programmable state and the new key registered via the OBD port, then tested end-to-end.

One-key households are most at risk

A lot of MGs — especially used ZS and HS SUVs — were delivered with a single smart fob. The day that one key is lost or fails, you are straight into an all-keys-lost, the most expensive version, with no fallback. The cheapest insurance is a programmed spare while you still have a working key — a quick, cheaper job than the full all-keys-lost it prevents.

The relay-theft angle

MG’s keyless SUVs are, like any keyless car, a potential relay-theft target — thieves amplify the fob’s signal from inside your house to unlock and start the car on the drive. Three habits cut the risk: keep the fob in a Faraday (signal-blocking) pouch, store the spare well away from the front door and windows, and — after any theft or lost fob — have the key re-coded so the missing one is disabled. If a key was stolen rather than mislaid, our stolen car keys service covers programming a new key and, where the system allows, de-registering the old one so it can no longer start the car.

Sort your MG key with Lock City

Lock City covers Bristol, Bath and South Gloucestershire for everything from a fob battery to a full all-keys-lost on modern SAIC-built MG. We come to you and cut and code the key to your MG3, ZS or HS at the roadside with current software and the correct blanks — no towing, no dealer wait. See all our MG key services, our lost car keys service, or car key programming. Because an all-keys-lost price depends on your exact model and key type, we do not quote fixed figures — give us your registration for an exact quote. Call 07967 097 899, Mon–Fri 8am–5:30pm.