If you own a keyless Mercedes-Benz GLC in Sutton Coldfield, where the key spends the night matters more than it used to. A key on a hook by the front door or in a bowl in the hallway may be only a few metres from the car. The car unlocks and starts when it believes the key is nearby, and a relay attack is built to make it believe exactly that. This post looks at relay theft on a keyless GLC, what a key pouch can and can't do, and the two Pandora systems we most often talk through with GLC owners in Walmley, Mere Green and Four Oaks.
The regional picture
The West Midlands region had the second-highest rate of vehicle offences in England and Wales in the year to March 2026: 6.3 per 1,000 people, behind London (9.3) and above the England and Wales average of 5.1 (ONS police force area data tables, year ending March 2026). Vehicle offences include thefts of and from vehicles and vehicle interference.
The law has caught up with the equipment too. Thatcham Research welcomed new offences under the Crime and Policing Act 2026, naming relay attack tools, CAN bus injection devices, signal jammers and emulators as the devices targeted (Insurance Edge). The maximum penalty is five years in prison, an unlimited fine, or both (GOV.UK factsheet).
What relay theft means for a GLC
In broad terms, a relay attack extends the reach of your keyless fob. The signal is picked up near the house and passed on to the car, which then opens and starts as if the key were in your pocket. Nothing is broken, because as far as the car is concerned the right key is present.
Is a key pouch enough?
A signal-blocking pouch is a sensible habit, and West Midlands Police include Faraday pouches in their advice on preventing car and vehicle theft. But it only helps if the key is in it every single time, and it does nothing about key programming through the diagnostic port or CAN injection, neither of which needs your key at all. That's where an aftermarket system comes in.
Two ways to protect a GLC
Pandora Microbot: stop the start
The Pandora Microbot is a compact CAN-bus immobiliser. It blocks the engine start until you're authorised by a Bluetooth tag, a PIN entered on the GLC's own steering-wheel or dashboard buttons, or both. A relayed signal doesn't provide that, so the car stays where it is. It holds a Thatcham Category 2e certificate, shows no LED once fitted, and needs no subscription. It doesn't track the car, so if you want tracking you'd pair it with a separate tracker.
Pandora Smart Pro: alarm, immobiliser and tracking
The Pandora Smart Pro is a fuller system: a Thatcham Category 1 alarm and immobiliser with GPS and GLONASS tracking, controlled from the Pandora Connect app or a smartwatch. It's self-monitored, so alerts come straight to you rather than to a monitoring centre. GSM airtime is free for the first six months, then £70 for six months or £125 for twelve. Pandora states that its optional anti-hijack function isn't Thatcham accredited, so we talk that through before fitting.
| Microbot | Smart Pro | |
|---|---|---|
| What it is | Immobiliser | Alarm, immobiliser and GPS tracking |
| Thatcham | Category 2e immobiliser | Category 1 alarm and immobiliser |
| Authorisation | Tag, PIN on the car's buttons, or both | Bluetooth tags, app or smartwatch, the car's own fob, or a phone call |
| Tracking | No | Yes, self-monitored |
| Subscription | None | GSM airtime after 6 months |
If you like the idea of tracking but don't need an approved alarm, the Pandora Smart combines an alarm, tracker and immobiliser released by an encrypted Bluetooth tag. It isn't Thatcham-approved, because it doesn't come with a siren.
GLC questions
My insurer wants a monitored tracker. Does the Smart Pro count?
Not on its own. The Smart Pro is self-monitored, with no monitoring centre. If your policy asks for a Thatcham S5 or S7 tracker, we'd fit one of those; our guide to S5 and S7 trackers explains the difference.
Will I notice the Microbot day to day?
Once you're authorised, the GLC drives exactly as before. If you choose tag authorisation, the tag in your pocket does the work; with a PIN, you press a short sequence on the car's own buttons before starting.
Can the Mercedes dealer still service it?
Yes. The Microbot's service mode, set from the app, lets the car start without authorisation while it's being worked on.
Check your GLC
Every system is matched to the exact model and year before we quote. Send us your GLC's details and we'll tell you which options fit, with a fixed quote before anything is booked. Get a quote, see our work across Sutton Coldfield, or read more about immobilisers.
