Symptoms
- Lost your only key or want a backup
- New blank key won't start the car
- Fob unlocks doors but car won't start
- Key was purchased online but isn't programmed
Likely causes
- CommonKey not yet programmed to the car's immobilizerModern keys contain a chip that must be matched to the car's computer before the engine will start.
- PossibleWrong key or fob purchased for the exact trim/yearKey electronics can differ by trim level or model year even for the same car name.
- PossibleAll original keys lost, requiring a full relearnIf no working key remains, the car's computer may need to be reset before a new key can be added.
What to do
- Confirm your car's exact year, make, model, and trim before buying any replacement key or fob.
- Decide between a dealer, which has factory equipment, and a mobile locksmith, which is often cheaper and can come to you.
- Have your ID and proof of ownership ready, since programming a key to your VIN typically requires this.
- If you still have one working key, bring it, since some programming methods use it to authorize the new one.
- If you have zero working keys, expect a longer and more expensive process, sometimes requiring towing to a dealer.
- Once programmed, test locking, unlocking, and starting the car with the new key before relying on it.
Tools and parts
Replacement key or fob shellSearch: “replacement key fob for your car make, model, and year”
When to call a pro
This job is best done by a dealer or licensed automotive locksmith who can verify ownership and program the key correctly.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.