2004 Acura RSX Key Replacement

2004 RSX key specs

Every RSX, base and Type-S alike, uses a chip key in the head and a separate keyless entry remote with FCC ID OUCG8D-355H-A on 314 MHz. Key blanks follow the model year: parts catalogs list the 2002-2005 cars under the Megamos 13 edge-cut blank (Ilco HD106) and put the 2006 model under the Philips ID46 blank (Ilco HD111) used on the TL and TSX. The remote appears in three-button and four-button versions and runs on a CR2025 battery. The key alone starts the car, while the remote only handles the locks and panic alarm.

What's specific to the 2004 RSX

The 2004 Acura RSX is the third of 5 model years in the RSX First generation (DC5) (2002–2006), so it shares its key system with the rest of that run, which makes replacement parts easy to source.

A 2004 Acura RSX is about 22 years old. Original keys are often worn smooth, and some factory remotes for cars this age are discontinued, so we may suggest a quality aftermarket remote or a separate fob. Because older immobilizers are simpler, all-keys-lost jobs on cars this age are usually more straightforward than on late models.

Key options for the 2004 Acura RSX

• Transponder (chip) key. There are two ways to give a new transponder key the right identity. Cloning reads the chip in a working key and writes that same ID onto a special cloneable chip, so the car can't tell the two apart. Programming adds a brand-new key ID to the immobilizer's memory through the OBD-II port, sometimes after entering a security PIN tied to the VIN. Cloning is handy when you have a working key and the chip family supports it. Programming is the better choice when keys are lost, because it also lets us remove keys you no longer control from the car's memory. For your Acura RSX, we'll explain which method fits and why.
• Key with separate remote fob. Pairing a separate remote to a 2004 Acura RSX is a different job from programming the ignition key. Some vehicles accept new remotes through an on-board sequence of key turns and button presses; others need a scan tool connected to the OBD-II port. On many of them, entering remote programming mode clears every remote the car already knows, so any remote you want to keep has to be present and re-paired during the same session. Before we start, gather every remote that belongs to the vehicle. Leaving one in a kitchen drawer is a classic way to end up with a remote that quits the day after a new one is added.

How the Acura immobilizer works on the RSX

Acura fitted an immobilizer to essentially every car it sold here from 2000 on, and the type of chip tells you a lot about how a replacement key gets made. Through the early 2000s, the TL, CL, RL, MDX, RSX, NSX and 2000-2001 Integra used a Megamos 13 fixed-code transponder inside a conventional key, with keyless entry handled by a separate remote. The 2004 TL and TSX introduced Philips ID46 (Hitag 2) crypto chips, which later moved into flip keys on the MDX, RDX, TL and TSX. The 2005 RL brought Acura's Keyless Access smart key, and by the late 2010s nearly every Acura used push-button start with a Philips ID47 (Hitag 3) smart fob. The newest designs, such as the 2022-and-later MDX and RDX, the 2023 Integra and the ADX, use Honda's latest smart key generation, while the electric 2024 ZDX uses a GM-designed system. In every case the engine computer checks the chip before it lets the engine run, so a key that is only cut will turn the ignition without starting the car. A flashing key symbol on the dash usually means the car didn't recognize the chip.

• Catalogs list the 2006 RSX under the same Philips ID46 key blank as the 2004-2006 TL and 2004-2008 TSX, so we check the chip type before cloning.
• The 2002-2005 RSX key uses the same Ilco HD106 blank as the 2001-2006 MDX and 1999-2003 TL.
• Match the OUCG8D-355H-A FCC ID when buying a replacement remote; similar-looking Acura remotes from the same years use different FCC IDs.

Programming a 2004 RSX key

On 2002-2005 cars the Megamos 13 chip is fixed-code, so a spare can often be cloned straight from your working key. A 2006 key with an ID46 chip has to be programmed to the car instead. If every key is gone, we cut a new one to the door lock and program its chip through the OBD-II port with a key programmer. The remote is a separate step and can usually be paired with Honda's on-board ignition routine.

Lost every key to your RSX?

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 Acura RSX 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 Acura RSX 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

• 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.
• 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.
• When you sell or trade in the vehicle, buyers and dealers expect two keys. A missing key can come up during an appraisal or a private-sale negotiation, so having both on hand keeps the conversation about the car, not about what it will cost the next owner to replace one.

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 RSX and your schedule.

RSX key battery

If a new CR2025 doesn't bring the fob back, the battery wasn't the problem. Common culprits include a battery holder whose solder joints have cracked from drops, contacts corroded by moisture, worn rubber button pads that no longer reach the circuit, or a board damaged by water. We can test whether the fob is transmitting at all and inspect the board closely. Sometimes a new shell or a resoldered holder solves it; sometimes the fob has to be replaced and programmed. Meanwhile, the car can usually still be started with the fob held at the backup spot described in the owner's manual.

How the job works

1. Identify the exact key your RSX uses. Every job starts with the VIN, the trim and a look at any key you still have. From those we confirm the keyway, the transponder or smart-key chip, the remote frequency, the FCC ID and the button layout. Two Acura RSX keys that look identical can carry different electronics, so this step keeps the wrong part from ever reaching the car.
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 Acura 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. Our van carries a code-cutting machine that handles both traditional edge-cut blades and the laser-cut, side-milled profiles common on newer keys. The blade is cut to the code, then test-fitted in a door lock and the ignition or emergency keyhole to confirm smooth operation before any programming begins.
5. Program the chip, remote or smart key. Programming tells the car's computers that the new key belongs to the vehicle. Transponder chips are added to the immobilizer, remote buttons to the body control module, and proximity fobs to the keyless system. If a step requires dealer-only access on your RSX, you'll have heard that before we arrived, not halfway through the job.
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 an RSX key

• The type of key. Price follows complexity. The more the key does, the more it costs to replace: brass blade, then chip, then remote buttons, then full keyless entry and push-button start. If your RSX came with different key styles by trim, the one your car actually uses is the one that sets the quote.
• 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 Acura system adds equipment time and labor to the job.
• Blade style and cutting. The blade still matters on keyless cars, because the emergency insert has to fit the door lock. Cutting by code is standard for us. Decoding a door lock when no key or code exists adds time, and so does progressing any cuts the door lock doesn't show.
• Travel, timing and extra repairs. Because we come to you, the distance from our San Bernardino base and the time of the call play a part. So does anything we find along the way, such as a worn ignition cylinder or a seized door lock. You hear about each item and get a quote before we start work.

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

Common Acura key problems

• No-start after a key is dropped or run through the wash. A damaged chip can leave the key turning the ignition, or the fob locking doors, while the engine refuses to start. Testing the transponder tells us whether the key needs replacing.
• Weak smart key batteries. Most Acura smart fobs from 2009 on take a CR2032 coin cell. With a dying battery, holding the fob against the ENGINE START/STOP button usually lets the car read its chip and start anyway.
• Four-button spares on remote-start cars. Some 2014 and later Acuras shipped with a five-button fob that includes remote engine start. A four-button replacement will drive the car but won't start it remotely, so count your buttons before ordering.

Tips from a mobile locksmith

• 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.
• 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.
• Photograph the back of your fob and any key tag that came with the car. The FCC ID, part number and key code printed there make ordering a replacement faster and more accurate. Store the photos somewhere you can reach from any device, not only on the phone that might go missing along with the keys.

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 2004 Acura RSX key?

Locked out, keyless, or just tired of a fob that only works half the time? Julian's Locksmith can help with your RSX in Southern California. Have your registration and photo ID ready, call (951) 903-3193, and we'll give you an honest answer about what we can do on-site and what it will cost before we head your way.