Why Has My Car Key Suddenly Stopped Working?
The usual culprits are a flat key battery, worn buttons, a damaged circuit board after a drop or a wash, interference in the area where you are parked, or a fault on the vehicle side such as the reader coil around the ignition. Whether the doors still respond narrows it down quickly.
Quick checks you can make
Working through these takes a couple of minutes and often identifies the fault.
- Try the spare key if one exists — if that works, the fault is in the first key
- Replace the key battery with a fresh one of the correct type
- Use the emergency blade hidden inside most smart keys to open the door manually
- Move the vehicle a short distance if you suspect radio interference
- Look for cracks in the shell or a rattle inside the key
Doors open but the engine will not run
That combination points at the transponder or immobiliser rather than the remote. The chip may have failed or lost its programming, or the reader around the barrel may not be picking it up.
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