The classic immobilizer symptom
When an engine catches for a moment and then stalls almost instantly, a very common cause is the immobilizer. The car lets the engine fire briefly, then realizes it does not trust the key and shuts the engine down to stop a theft. A security light flashing right as it dies is a strong sign of this.
This pattern often appears with an unprogrammed or poorly cloned key, a chip that is failing, or a key the car has stopped recognizing. The blade turns fine and the starter works, which is why people are surprised the engine will not stay running.
How to tell it apart from engine faults
Not every start-and-die is the key. A clogged fuel system, a failing fuel pump, a vacuum leak, or an anti-theft fuel cutoff can all cause a quick stall. Watch the dash: a flashing security or key icon points to the immobilizer, while a check-engine light or rough running before the stall points more toward a fuel or engine issue.
If you have a spare key, try starting with it. If the spare keeps the engine running and the usual key does not, you have found your answer and the daily key needs attention.
How a locksmith helps
When the immobilizer is rejecting the key, a mobile locksmith can test whether the chip is being read, reprogram a key the car should already trust, or cut and program a fresh key the immobilizer will accept. That usually clears a start-and-die caused by the key.
If the problem turns out to be fuel or engine related, that is a job for a mechanic, and we will tell you honestly when that is the case. Call us with your year, make, and model and we will diagnose the key side on site in West Palm Beach.
Still have a key or fob question?
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