2020 Mercedes-Benz GLB Key Replacement

2020 GLB key specs

Every GLB starts with a button, and the fob just has to be in the cabin. All cars open from the fob buttons, while those equipped with Keyless-Go also open when you grip a door handle with the fob nearby. The key matches the style used on the second-generation GLA and the CLA of the same years, with lock, unlock, liftgate and panic buttons and a slide-out emergency key for the driver's door. GLB 250 and AMG GLB 35 models, with two or three rows of seats, use the same system.

What's specific to the 2020 GLB

2020 was the first model year of the GLB X247 (1st generation). Early-production cars sometimes use different part numbers than later ones, so for a 2020 Mercedes-Benz GLB we confirm the exact key from the VIN or the old key's FCC ID before cutting anything. A 2020 Mercedes-Benz GLB is about 6 years old now. Original fob batteries are near the end of their life at this age, so weak range or a "key not detected" message is often a battery before it is a failed fob. Cars this age are often on their second owner, which is when a single remaining key and a request for a spare tend to show up.

Smart-key cars like the 2020 GLB can be targeted with relay attacks that extend the fob's signal from inside your home, so keep fobs away from exterior walls or in a signal-blocking pouch, and have any missing fob erased from the car.

Key options for the 2020 Mercedes-Benz GLB

• Smart proximity key (push-to-start). Proximity keys bring a security trade-off worth understanding. Because the fob is always listening, thieves with relay equipment can stretch its signal from inside your house to the car in the driveway. Keeping the fob away from exterior walls, or in a signal-blocking pouch, closes that gap, and some fobs offer a sleep mode described in the owner's manual. If a smart key for your 2020 Mercedes-Benz GLB is lost or stolen, programming a replacement is the moment to delete the missing fob from the car's memory. And be wary of used fobs from online sellers: a lot of them are locked to the vehicle they came from and can't be reprogrammed to yours.

How the Mercedes-Benz immobilizer works on the GLB

Mercedes-Benz calls its immobilizer the Drive Authorization System, and for key work it helps to sort the cars into three eras. The oldest models we cover, such as the 2000-2002 E-Class, the last W202 C-Class and the first CLK, use a key with remote buttons in its head and an HU64 two-track blade that turns a conventional ignition lock while the immobilizer checks electronics inside the key. The next era, known in the trade as FBS3 or DAS 3, came to the US on the S-Class and CL around 2000 and spread to nearly every model within a few years. Its key is a fob that plugs into an electronic ignition switch and identifies itself by infrared: chrome-bodied at first, then the familiar black fob with chrome sides. Keyless-Go let many of these cars open and start with the fob left in a pocket. Around 2014 and 2015, Mercedes began moving models to FBS4, and push-button start gradually became standard. FBS4 keys are produced by Mercedes-Benz for one VIN, which is why most newer cars mean a dealer order.

• Because each key is coded to one VIN at Mercedes-Benz, a used fob from another GLB cannot be made to work in yours.
• A dealer can block a lost key from starting the car, worth doing if the fob disappeared along with something showing your address.
• Many fobs of this era can be put to sleep with a double press of the lock button, a simple guard against relay theft.

Getting a 2020 GLB key from the dealer

There is no on-site programming route we offer for the GLB. Mercedes-Benz produces each key for one VIN, a dealer places the order after checking your ID and ownership documents, and the finished key generally works as soon as it is used in the car. When you call us, we handle the urgent parts: opening a locked GLB, testing whether a fob that quit only needs a fresh battery, and using the emergency key so the car can be locked until the new fob arrives.

GLB keys are built by Mercedes-Benz for the VIN and ordered through a dealer; we handle lockouts and fob troubleshooting.

How we help when the key must come from Mercedes-Benz

With every key gone, the era matters again. On many FBS3 cars, we remove the electronic ignition switch, read it on the bench and calculate a new key from the car's own data, with no working key to copy. That takes longer than making a spare, and a few switches or control units won't cooperate, but it often saves a tow to the dealer. For FBS4 cars and for the oldest pre-FBS3 models, the dependable route is a key built by Mercedes-Benz for your VIN and ordered through a dealer after you show ID and proof of ownership. While that order is filled, we can open the car without damage so you can reach documents or belongings, and a dealer can block the lost keys so they no longer start the car.

1. Get you back into the car. If the car is locked, we open it on site without damage, so you can reach the registration, the VIN plate and anything you need inside.
2. Line up the dealer order. We help you gather what the Mercedes-Benz dealer will ask for: the VIN, current registration or title, and photo ID in the owner's name. That avoids a second trip.
3. Keep the car where it is if possible. Ask the dealer whether the key can be programmed with the car in place or whether it needs to be towed in. Some brands deliver a pre-coded key; others must program it at the vehicle.
4. Plan for a spare. Once you have a working key, order a second one. Losing the only key on a dealer-only system is the slowest and most expensive situation to recover from.

Why the 2020 GLB needs a dealer key

Some keys can't be made outside the factory network, and the 2020 GLB is one of them. Mercedes-Benz generates the key data on its own servers and ties it to the car's VIN, so a new key is either pre-coded before it ships or programmed at the vehicle with an online session that only authorized dealer equipment can open. Aftermarket tools that handle older Mercedes-Benz models can't complete that handshake on this generation, at least not reliably today. That is a security feature: it is the reason relay and key-cloning thefts are harder on cars like this.

What to bring to the dealer

Before you call the dealer, collect three things: proof of ownership (registration or title), photo ID with the same name, and the 17-character VIN. Write down which keys you still have and whether any of them still start the car. That one detail changes the order, the price and whether the car has to be at the dealership for programming.

While you wait for the new key

Waiting on a factory key can take anywhere from the same day to a week or more, depending on stock. In the meantime, avoid buying a used key online; on dealer-only systems a used key almost never programs to a different car. If you're locked out of the car or need something from inside it, call us; that part is quick and doesn't depend on the dealer.

What affects the dealer's price for a GLB key

Expect the dealer's quote to include the key itself, a programming or setup charge, and sometimes a separate charge for cutting an emergency blade. If every key is lost, add the cost of getting the car to the dealership. Comparing two dealers is worth a phone call; programming charges vary more than the price of the key.

Avoid doing this twice

Once you have a working key for your 2020 GLB, order a second one while the car's information is already on file. On dealer-only systems, adding a key while one still works is simpler, faster and cheaper than replacing every key after a loss. Keep the spare somewhere you can reach quickly, not in the car, and note where you stored it.

GLB key battery

Most fobs for a 2020 Mercedes-Benz GLB open along a small slot in the seam; a coin or a plastic pry tool works better than a screwdriver, which chews up the housing. If the fob hides a mechanical blade, slide it out first, since the case often opens from that gap. Note which side of the old cell faces up, swap in a fresh replacement, and press the halves together until they click all the way around. Handle the new battery by its edges, because skin oil on the faces can hurt contact. In most cases the fob keeps its programming through a battery change, so test lock, unlock and start, and you're done.

Common Mercedes-Benz key problems

• Mercedes keys are written to one car, so a secondhand fob bought online usually can't be programmed to yours. New keys made for your car, or keys ordered by VIN through a dealer, are the options that work.
• Inland Empire summer heat shortens coin-cell life and is hard on fobs left on a sunny dashboard. If a Mercedes key starts responding only at close range, a new battery is the simplest first step.
• The black Mercedes fob with chrome sides takes a CR2025 coin cell, and a small lamp on the fob flashes when you press a button. If the lamp stays dark or the remote stops working, try a fresh cell before ordering a key.
• Every Mercedes smart key hides a mechanical emergency key that slides out of the fob. Many owners never notice it until the fob or the car's 12-volt battery dies and the driver's door has to be opened by hand.
• The electronic steering lock is a known weak point on the W204 C-Class and the W212 and W207 E-Class. When it fails, the key goes in but won't turn and the dash stays dark, and a new key will not fix it.

Tips from a mobile locksmith

• Be careful with discount fobs from online marketplaces. A listing may match your remote's shape while using a different frequency, chip or FCC ID, and many used smart keys are locked to their original vehicle. If you already bought one, send us the listing or a photo before the visit so nobody pays for a programming attempt that can't work.
• On any vehicle with a turn-key ignition, keep the key ring light. A heavy cluster of keys, tools and charms swings with every bump and slowly wears the ignition wafers and the key itself. When the key starts to stick or needs a wiggle to turn, deal with it early, before it stops turning entirely.
• If your vehicle has a proximity key, think about where it sleeps at night. A fob hanging by the front door can sit within range of relay equipment used to open and start cars from outside. A drawer deeper inside the house, a signal-blocking pouch, or the fob's own sleep mode reduces that risk considerably.
• Never hide a spare key or fob on the outside of the car. Magnetic boxes in wheel wells and under bumpers are the first places a thief checks, and with a proximity fob, a hidden key can let anyone open the doors and drive away. Keep the spare at home or with someone you trust.
• Learn your car's dead-fob start method now, in the driveway, rather than in a dark parking lot later. Depending on the make, you hold the fob against the start button or place it in a marked pocket in the console. Also find the hidden keyhole on the driver's door handle and practice using the emergency blade.

Proof of ownership

Before we cut or program a key for any vehicle, we verify that you have the right to it. Please have two things ready: the current registration or the title, and a government-issued photo ID with a matching name. We also check that the VIN on those documents matches the VIN plate on the dashboard. If the registration is locked inside the car, that's fine; we open the vehicle first, check the paperwork in the glove box, and only then make the key. If something doesn't line up, we stop and sort it out before any key is made.

Need a 2020 Mercedes-Benz GLB key?

Call Julian's Locksmith at (951) 903-3193 if you're locked out of a 2020 Mercedes-Benz GLB or need help preparing a dealer key order. We'll tell you plainly what we can do on site and what has to go through Mercedes-Benz.