2018 Chrysler 300 Key Replacement

2018 300 key specs

The redesigned 300 went to proximity entry and push-button start, and most supplier listings show smart keys for these years. The fob has four buttons (lock, unlock, trunk, panic), or five with remote start, and a release on the side frees an emergency blade for the driver's door. Through 2018 it is listed under FCC ID M3N-40821302 with a Philips ID46 (Hitag2) chip, the same unit used on the Dodge Charger of those years. A few catalogs also list the older fobik-style proximity fob, IYZ-C01C, for some 2011–2015 cars, so match the FCC ID on your original.

What's specific to the 2018 300

2018 was the final model year of the 300 LD (2nd generation, ID46 smart key), before the LD (2nd generation, AES smart key) arrived for 2019. Late-run cars occasionally pick up running changes, so we check the VIN instead of assuming a 2018 Chrysler 300 matches a 2011. At roughly 8 years old, a 2018 Chrysler 300 has usually seen real wear. Fob cases crack, buttons wear through and solder joints loosen at this age, so a new shell or a replacement remote often beats repairing the old one. Many have changed hands more than once, so erasing keys you can't account for is worth doing during the visit.

Smart-key cars like the 2018 300 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 2018 Chrysler 300

• 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 Chrysler 300 LD (2nd generation, ID46 smart key), 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 Chrysler immobilizer works on the 300

• From 2018 the 300 has a secure gateway module, and aftermarket programmers need a bypass cable or authenticated login to finish key work.
• The 2015 refresh changed styling and the interior but kept the M3N-40821302 ID46 smart key through 2018.
• Supplier fitment lists the same fob for the 2011–2018 Charger and 2015–2018 Challenger, but each fob must be programmed to its own car.

Programming a 2018 300 key

New smart keys are programmed through the OBD-II port with a tool that obtains the 4-digit PIN and writes the fob to the car's radio frequency hub. Adding a key and all-keys-lost follow nearly the same path, since no blade has to start the engine. On 2018 cars the factory secure gateway module blocks many aftermarket tools from writing data, so a bypass cable or authenticated access becomes part of the job.

Lost every key to your 300?

Losing every key is usually recoverable on a Chrysler without towing it to a dealer. For bladed keys, we decode a door lock or cut by code from the VIN record after confirming you own the vehicle, then program a new transponder or remote-head key through the OBD-II port. Fobik-equipped vans and sedans need no ignition cut, so that work is mostly electronic plus a new emergency insert for the door. The harder cases are the AES-encrypted smart keys on the Pacifica, Voyager, 2015–2017 200 and 2019–2023 300, where some vehicles need the radio frequency hub handled directly or a dealer visit, and the Crossfire, whose Mercedes-derived keys are normally ordered pre-coded. We tell you which case applies before we drive out.

1. Gather your documents and the VIN. Call with the year, make, model and VIN if you can read it through the windshield, plus where the car is parked. Those details let us confirm whether your Chrysler 300 can be done on-site and bring the right key, so the first trip is the only trip.
2. Get into the vehicle without damage. Entry comes before key-making because we need access to the ignition, the OBD-II port and sometimes the documents in the glove box. We take care with weather stripping, door frames and paint, and we confirm the dash VIN matches your registration before going any further.
3. Originate a new key from the car. With no key to copy, the cuts come from the vehicle itself. We retrieve the key code through manufacturer channels where possible, or decode a door lock with a pick-decoder tool. Then we cut the blade on our code machine and confirm it turns the lock smoothly.
4. Program the key to the immobilizer. All-keys-lost programming often takes longer than adding a key, because the car has no trusted key to authorize the change. We follow the procedure your Chrysler 300 requires, then confirm the engine starts and keeps running and the remote or keyless functions respond.
5. Erase missing keys and add a spare. Once the car starts, we remove the lost keys from memory wherever the system allows, so they can't start the engine if someone finds them. Making a second key during the same visit costs much less than a repeat all-keys-lost call down the road.

Why a spare key pays for itself

• Some vehicles make it hard to add a key once you're down to one. Certain immobilizer systems let an owner program an extra key on-board only when two working keys are present, so a second key preserves the easy options for later and avoids a full reset.
• A spare stored safely at home rescues you from a locked car with the fob sitting on the seat, a key dropped somewhere along a hiking trail, or a fob that stops responding on a busy morning. Keep it indoors, never in a magnetic box under the bumper.
• Electronics fail without warning. A fob dropped on concrete, run through the washing machine or soaked at the pool can quit for good. With a second programmed key, that's an annoyance you fix on your own schedule, not a stranded car that needs attention today.

Dealer or mobile locksmith?

Price and parts are the other half of the comparison. Dealers typically sell factory keys only and charge their posted service rates for programming. We offer factory keys where it matters and quality aftermarket alternatives where they perform well, and the quote covers cutting, programming and the trip, with nothing tacked on at the end. Timing differs too. Dealer service departments generally keep business hours, while we take automotive calls every day from 6:30 a.m. to 11:30 p.m., which covers early commutes and late evenings. We're closed overnight, and we'll be upfront if your timing means the dealer or a next-day visit is the better plan. Neither option is wrong; the right one depends on your 300 and your schedule.

300 key battery

Most fobs for a 2018 Chrysler 300 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 CR2032, 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.

How the job works

1. Identify the exact key your 300 uses. We ask a few quick questions on the phone: the year, whether the car starts with a turn key or a button, how many keys you have left, and whether the remote still works the doors. Then we check the VIN against our programming references so the van arrives with the correct blank or fob, not a close guess.
2. Verify ownership before any work. California holds licensed locksmiths responsible for knowing whose car they're making keys for. We record your name, the VIN and the plate on a work order. If you aren't the registered owner, you'll need the owner's written authorization along with your own photo ID before we begin.
3. Get the key code or decode the lock. If you still have a working key, we can read its cuts directly and check them against the factory depths for the Chrysler keyway. A worn key gets corrected back to spec during this step, so the new key turns crisply instead of reproducing years of wear in a fresh piece of metal.
4. Cut the blade on-site. Cutting happens right beside your car. For a smart key, that means the emergency blade hidden inside the fob; for a transponder or remote-head key, it's the main blade you'll use every day. We deburr the cuts and check the fit in each lock so nothing binds or sticks later on.
5. Program the chip, remote or smart key. With the blade done, we connect to the OBD-II port and register the new key with the immobilizer. Depending on the Chrysler system, this may involve a security PIN, a timed waiting period, or on-board button sequences for the remote. On some vehicles we clone a working key's chip instead, when that's the more reliable path.
6. Test everything and clear out old keys. Before we leave, every function gets checked: doors, trunk or liftgate, panic button, remote range, engine start, and the emergency blade in the driver's door. If keys are missing, we delete them from the car's memory where the system allows, so a lost key can no longer start the engine.

What affects the price of a 300 key

• The type of key. The biggest factor is technology. A plain mechanical key is a cutting job only. A transponder key adds a chip and programming. Remote-head and flip keys add a circuit board, and a proximity fob for a push-button Chrysler 300 is the most involved of all, both in the part itself and in the programming.
• Factory or aftermarket parts. Some owners want an exact factory match; others just want a dependable key that starts the car. Both are reasonable choices. The part you pick changes the quote, so we lay out the options side by side, with the trade-offs in fit, button feel and long-term durability, before you decide.
• All keys lost or adding a key. On some vehicles, losing the last key changes the programming entirely, from a quick add-key procedure to a full immobilizer reset or a module read on the bench. That extra labor shows up in the price, and it's the strongest argument for keeping a spare in the house.
• Programming complexity and security access. Some immobilizers accept a new key with a few on-board steps. Others need a PIN code, a timed security wait, manufacturer online access, or removing a module to read its data. Every extra layer of security on the Chrysler system adds equipment time and labor to the job.

Call (951) 903-3193 with your VIN and the keys you still have, and we'll quote the job before any work starts.

Common Chrysler key problems

• The 2018 and 2019 Chrysler 300 smart keys look identical but carry different transponder chips and different FCC IDs, M3N-40821302 versus M3M-40821302. Ordering by appearance alone leads to a fob that will not program, so match the model year and part number.
• A remote that only works from a few feet away usually needs a fresh battery. Fobs from 1999–2006 use CR2016 coin cells, while most later remote-head keys, fobiks and smart keys take a single CR2032. Inland summer heat is hard on these cells, so the battery is the first check.
• Sebring orders get mixed up often: the sedan and convertible use Chrysler keys and fobs, while the 2001–2005 Sebring coupe uses Mitsubishi-based keys and remotes that fit none of the other Sebrings.
• On 2018 and newer Chryslers, the secure gateway module blocks many aftermarket scan tools. Key programming still works with a bypass cable or authenticated access, which is why a shop without that setup may tell you only the dealer can help.

Tips from a mobile locksmith

• Every so often, use the mechanical blade in the driver's door lock. Cylinders that go years without a key can seize from dust and dried grease, and you won't find out until the day the fob dies and the blade is your only way in. A small shot of dry lubricant keeps the lock ready.
• 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.
• 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

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 2018 Chrysler 300 key?

Need a key for your 2018 Chrysler 300? Call Julian's Locksmith at (951) 903-3193 with your VIN and tell us which keys you still have. We'll confirm what the job involves, give you a quote before any work starts, and come to you in Southern California with everything needed to cut and program the key on the spot.