Anti-Theft System Signal Engine Disabled

What this code means

The anti-theft immobilizer system has detected an unauthorized start attempt and has disabled the engine. The PCM will not allow fuel injection or ignition until proper key authentication is received.

Symptoms

• Engine cranks but will not start
• Security light flashing on dashboard
• No fuel delivery or spark
• Engine starts then immediately dies

Common causes

• Key transponder not recognized
• Faulty immobilizer antenna around ignition
• Incorrect or damaged key
• Immobilizer module failure
• Low key battery (push-button start systems)

Diagnostic steps

1. Try a second programmed key
2. Check security indicator light behavior
3. Inspect immobilizer ring antenna around ignition cylinder
4. Verify key programming status with scan tool
5. Check key battery if applicable

Repair notes

Try a different programmed key first; reprogram keys or replace the immobilizer antenna if faulty.

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