Car Key Fob Not Working? What to Check First
The doors stopped unlocking from the button. Maybe the car will not recognise the key at all, and you are standing next to it pressing harder, which never helps.
Before you pay anyone, there are four things worth checking. Two of them cost nothing.
Why has my key fob stopped working?
Most of the time it is the battery. A coin cell in a fob lasts roughly two to four years and fails gradually — range gets shorter for weeks before it stops entirely.
After that, the usual causes are a cracked solder joint from being dropped, water damage, a worn button contact, or the fob losing its pairing with the car.
Programming a replacement or re-pairing an existing fob commonly costs around $60 to $150 depending on the vehicle, on top of the fob itself if you need a new one.
Check these four things first
- The battery. A CR2032 or CR2025 costs a couple of dollars. If the range had been getting shorter, this is almost certainly it.
- The spare. If the second fob works normally, the car is fine and the problem is in the first fob. If neither works, look at the car instead.
- The mechanical key. Most fobs hide a metal blade that opens the driver’s door. If that works, you are not locked out, whatever the buttons do.
- The car battery. A car too flat to run its receiver will ignore a perfectly good fob. Check whether the interior lights and dash come up normally.
When it is the fob and when it is the car
The spare key test settles it. Two fobs failing at once is rarely two coincidences — it points at the car’s receiver, a blown fuse, or a flat battery.
One fob failing while the other works is the fob: battery, board, or a lost pairing.
There is a third case worth knowing. If the car starts when you hold the fob against the start button or the steering column but not otherwise, the transponder chip is fine and the remote side is what has failed. That usually means a battery or an antenna problem, not a new key.
Push-to-start cars
A proximity key that has stopped being detected is a slightly different problem. The car is listening for the key continuously, so a weak battery shows up as intermittent detection first — it works some mornings and not others.
Nearly every push-to-start car has an emergency position for a dead key, usually a marked spot on the steering column or a pocket in the centre console. The handbook says where. That gets you home; it does not fix the key.
What programming involves
A fob has to be introduced to the car before it will be trusted. That is done through the diagnostic port with equipment that talks to the immobiliser, and it takes a few minutes once the right procedure is selected for the vehicle.
Two things worth knowing. Some vehicles erase every existing key when a new one is added, so bring all your keys to the appointment or you will be paying to program the others again. And a fob bought online is often a different variant from the one the car expects — check the part number before buying, or let whoever programs it supply the fob.
Need this done? See our Key fob programming page, or call (425) 675-6617 and tell us what you have.
OUR LOCKSMITH SERVICES
Fast mobile locksmith service for cars, homes, keys, and emergency lockouts
Car Key Replacement
Lost or broken car key? We cut and program a new one on the spot.
All Keys Lost
No working key at all? We originate a new key from the vehicle itself.
Car Lockout
Keys shut inside the car? We open the door without damaging it.
Commercial
Office and storefront locks, master key systems, rekeys and exit devices.
Ignition Repair
Key will not turn, or the ignition feels stuck? We diagnose and repair it.
Residential
Home lockouts, rekeys, lock repair and new lock installation.
Need HELP ASAP?
Call KeyHub Locksmith for fast mobile service
Where We Can Unlock Your Car
We come to where your car is locked
Our mobile car lockout service is designed for real-life situations. We can come to your home, workplace, apartment complex, shopping center, parking lot, roadside location, gym, school, or wherever your vehicle is parked.
LICENSED & INSURED
Professional, reliable service you can trust
MOBILE SERVICE
Our fully equipped technicians come to you
FAST RESPONSE
We aim to arrive quickly when you need us most
Need a mobile locksmith
near you?
Call now and we’ll let you know how fast we can get to your location.
CALL NOWFrequently Asked Questions
Quick answers about car key replacement, lockouts, key fob programming, and mobile locksmith service across Puget Sound
Usually yes. Most fobs open with a coin or a small screwdriver along the seam, and the cell is a standard CR2032 or CR2025. Note which way up the old one sits before taking it out.
On most vehicles, no. The pairing is stored in the fob’s memory and survives a battery change. A few models need the remote resynchronising, which is usually a sequence of door lock presses described in the handbook.
Commonly $60 to $150 depending on the vehicle, plus the fob if you need one. Newer vehicles with encrypted immobilisers sit at the higher end.
Often, if it is the right variant for the vehicle. Bring the packaging and the part number. Aftermarket fobs vary in quality and some cannot be paired at all.
That points at the transponder side rather than the remote side, or at something unrelated to the key — a flat battery, a starter fault, or a worn ignition cylinder. Worth diagnosing before ordering a key.
STILL HAVE QUESTIONS?
Call KeyHub Locksmith for fast mobile service