Security / Immobilizer / Anti-Theft
Caution — Service soon
What It Means
The vehicle's immobilizer system does not recognize the key or there is a security system fault. This may prevent the engine from starting, or the light may come on while driving, indicating a system fault.
Common Causes
- Key fob battery is dead or very weak
- Transponder chip in key not recognized
- Faulty immobilizer antenna ring around ignition
- ECU/immobilizer synchronization lost
- Aftermarket alarm system interfering
- Body control module (BCM) fault
Can I Still Drive?
If the vehicle starts: yes, but address the issue soon — the vehicle may fail to restart. Try your spare key if available. If the vehicle won't start: turn ignition to ON for 10 minutes (some vehicles re-learn the key), or use a spare key.
Estimated Repair Cost
$50 – $1,200
This is an estimate only. Actual costs vary by vehicle make, model, year, location, and shop labor rates. Always get multiple quotes for major repairs.
Related OBD-II Trouble Codes
These OBD codes are commonly associated with this warning light. Scan your vehicle with an OBD-II scanner to get the exact code before diagnosing.