2020 Mercedes-Benz GLA Key Replacement

2020 GLA key specs

Most first-generation GLAs start the way older Mercedes models do: the fob slides into an ignition slot on the dash, to the right of the steering column, and turns. Cars ordered with Keyless-Go have a start button in that slot instead and open when you grip the door handle, and the button can be pulled out so the fob can go in. The fob carries lock, unlock, liftgate and panic buttons and hides a slim emergency key for the driver's door. The AMG GLA 45 uses the same key layout as the GLA 250.

What's specific to the 2020 GLA

2020 was the final model year of the GLA X156 (1st generation), before the H247 (2nd generation) arrived for 2021. Late-run cars occasionally pick up running changes, so we check the VIN instead of assuming a 2020 Mercedes-Benz GLA matches a 2015.

A 2020 Mercedes-Benz GLA 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.

Key options for the 2020 Mercedes-Benz GLA

• Remote head key. Remote-head keys look similar across many vehicles, but the electronics inside are not interchangeable. Getting the right one for a Mercedes-Benz GLA means matching the FCC ID and part number printed on the back or inside the case, the operating frequency, which is commonly 315 MHz on US-market cars, the transponder type, and the button layout. A trim with remote start or a power liftgate may use a four- or five-button version where a base trim uses three. We check those details against your VIN and your existing key, if you have one, before cutting the blade. A wrong match can look perfect and still refuse to program.
• Smart proximity key (push-to-start). Making a new smart key is mostly a programming job. The fob has to match the vehicle's FCC ID, frequency and chip, and then the keyless system must be told to accept it, normally through the OBD-II port. Depending on the platform, that can mean entering a PIN, waiting through a timed security procedure, or on some newer vehicles, using manufacturer online access. When every key is lost, certain models need a module removed and read on the bench. For your Mercedes-Benz GLA X156 (1st generation), we'll tell you which of those applies, and if a step is dealer-only, you'll hear it before we drive out. The emergency blade hidden inside the fob is cut by code during the same visit.

How the Mercedes-Benz immobilizer works on the GLA

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.

• The GLA shared its platform and much of its key hardware with the 2014-2019 CLA, a useful clue when reading supplier listings.
• A red battery check lamp on the fob should flash briefly with each press while the battery is healthy.
• A Mercedes dealer can block a lost key so it can no longer start the car.

Getting a 2020 GLA key from the dealer

GLA keys are tied to the car through Mercedes' drive authorization system, and for most US cars a new key has to be produced by Mercedes-Benz for the VIN and ordered through a dealer. We check your VIN first, because aftermarket coverage depends on the exact control unit in the car and changes over time. When the dealer route applies, we can still open a locked GLA, test the fob and its battery, and make sure you have the ID and registration the dealer will want.

Plan on a dealer-ordered key for most GLAs; we check by VIN, handle lockouts and help with fob problems.

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 GLA needs a dealer key

On the 2020 GLA, the immobilizer and the keyless system trust only keys that Mercedes-Benz's own system has authorized for that VIN. Programming happens through a secure online connection, and the key itself is usually ordered with the car's security data already written to it. Independent locksmith equipment is very capable on most vehicles, but on dealer-only generations like this one the honest answer is that the factory has to be involved. Being upfront about that saves you the cost of a wasted service call.

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

While the dealer key is on order, protect what you have. If one key still works, keep it indoors and away from the car, and don't hand it to anyone you wouldn't trust with the car itself. If the car is locked with belongings inside, we can open it without damage. If the key has a mechanical emergency blade, ask us about cutting a spare blade by code so you can at least lock and unlock the doors.

What affects the dealer's price for a GLA key

Dealer key pricing depends on the key type (a smart key costs more than a basic remote key), whether the car needs to be at the dealership for programming, the dealer's programming or labor charge, and whether a tow is involved because no working key remains. Ask for the total, parts plus programming plus any tow, before you agree, and ask whether ordering two keys at once lowers the per-key cost.

Avoid doing this twice

Once you have a working key for your 2020 GLA, 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.

GLA key battery

Most fobs for a 2020 Mercedes-Benz GLA 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.
• On dash-slot Mercedes models from the mid-2000s to the mid-2010s, a key that slides in but won't turn often points to a worn electronic ignition switch or a weak car battery rather than a bad key. We test both before replacing anything.
• 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.

Tips from a mobile locksmith

• When a key's head cracks or its blade bends, replace it before it fails. A transponder chip can slip out of a split head, and a bent blade can break off inside the ignition or door lock, turning a simple key replacement into an extraction and repair job. Small symptoms are the inexpensive time to act.
• 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.
• 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.
• Southern California heat is hard on keys. Fob batteries drain faster, plastic housings turn brittle, and rubber button pads crack when a key spends summer afternoons on a dashboard or in a sunny cup holder. Carry the fob with you or keep it shaded, and replace batteries before summer rather than after they fail.
• 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.

Proof of ownership

Not every situation fits the simple case, so here's how we handle the common exceptions. For a leased or financed vehicle, a registration that lists you as the registered owner or lessee works with your ID. If you just bought the car, bring the signed title or bill of sale along with your ID. For a company or fleet vehicle, we need written authorization from the business plus the driver's ID. If the car belongs to a family member, the registered owner should be present or provide signed permission and a copy of their ID. Rental vehicles go through the rental company.

Need a 2020 Mercedes-Benz GLA key?

Call Julian's Locksmith at (951) 903-3193 if you're locked out of a 2020 Mercedes-Benz GLA 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.