Key takeaways
- Most cars since the late 1990s need a key with a programmed transponder chip.
- A dead fob is often just a battery. Try that first.
- Making a spare from a working key costs far less than replacing the last key.
- A mobile locksmith can often cut and program a new key where the car is, avoiding a tow.
- Bring photo ID, proof of ownership and the VIN.
In this article
A missing car key used to mean a trip to the hardware store. Today it can mean a chip, a remote, a proximity sensor and a computer that has to learn the new key. Here is what you are dealing with, and how to keep the cost down.
First, is the fob really dead?
If the fob still exists but stopped working:
- Replace the battery. Most fob batteries are coin cells you can swap in minutes, and cold weather finishes off weak ones. See frozen car doors and locks.
- Use the hidden key. Most fobs have a metal emergency blade inside for the driver's door.
- Check the car's backup spot. Many push-to-start cars can read a fob with a dead battery if you hold it against a marked spot or put it in a slot. Your owner's manual shows where.
If the battery is fine and the buttons still do nothing, or the car says "key not detected", the fob may need reprogramming or replacing.
The kinds of car keys
| Key | What it is | Common on |
|---|---|---|
| Basic key | Plain metal blade, no chip | Older cars |
| Transponder key | Chip in the plastic head talks to the car's immobilizer | Most cars since the late 1990s |
| Remote head key | Transponder key with lock and unlock buttons built in | Many 2000s and 2010s cars |
| Flip key | Laser-cut blade folds into the fob | Many European and Korean models |
| Smart or proximity key | Stays in your pocket; push-button start | Most newer cars |
The transponder chip is why a cheap copy of the blade will open the door but will not start the engine. The car's immobilizer looks for a chip it knows, and a new key has to be programmed to the car.
Spare key vs all keys lost
This is the single biggest factor in what you pay.
You have one working key. Making a spare means cutting the blade and programming the new chip or fob while the car still recognizes a working key. It is usually the quickest and least expensive case.
Every key is lost. The new blade is cut from the vehicle's key code, the new key is programmed from scratch, and for security it is smart to erase the lost keys from the car's memory so they cannot start it. More work, more cost.
The lesson: if your car has only one key, get a spare made now, while it is still the quick and less expensive case.
Dealer or locksmith?
| Question | Dealer | Mobile locksmith |
|---|---|---|
| Comes to the car | Usually no | Yes |
| If no key works | Tow the car in | Key made where it is parked |
| Newest models | Can do all | Can do many, not all |
| Hours | Service department hours | Often 24/7 |
| Price | Often higher | Often lower |
For many cars, a mobile locksmith can cut and program the key in your driveway or the parking lot. For some brand-new or high-end models, the dealer may be the only option. A locksmith should tell you that on the phone, not after showing up.
What to have ready
- Year, make and model, and whether it is push-to-start
- The VIN, visible through the windshield on the driver's side, or on your registration and insurance card
- Photo ID and the title or registration in your name
- Where the car is, if it cannot be moved
Expect a locksmith to check ownership before making a key. A locksmith who does not ask is one you should worry about.
About online fobs
Online fobs can save money, but many are the wrong frequency, chip or model year, and some cannot be programmed at all. Send the part number and your vehicle details to your locksmith before you buy, and ask whether they will program customer-supplied fobs.
Need a car key in the Twin Cities?
SOS Locksmith Solutions cuts and programs car keys on site across Minneapolis, St. Paul and nearby suburbs, 24/7. Call 763-600-3529 with your year, make and model for a price, or read about car key replacement.
Questions people ask
Can a locksmith program a key fob?
For many makes and models, yes, on site. Some newer vehicles can only be programmed by the dealer. A locksmith will tell you which when you give the year, make and model.
Do I need the original key to get a new one?
No. A locksmith can cut a new key from the vehicle's key code and program it, with proof of ownership. It takes longer and costs more than copying a working key.
Should I buy a cheap fob online?
Be careful. Many online fobs are the wrong frequency, chip or model, or cannot be programmed. Check with your locksmith using the part number before you buy.
Written by the SOS Locksmith Solutions teamFamily-owned 24/7 locksmith based in Crystal, MN. Updated .
