Red Key symbol or car with a key/lock icon Light: Immobilizer Light Warning Light
⛔
Stop - May Not Start
The vehicle's security immobilizer has activated. The key is not being recognized or the anti-theft system has triggered.
📋 What This Light Means
| Light Color | Red |
| Symbol | Key symbol or car with a key/lock icon |
| Meaning | The vehicle's security immobilizer has activated. The key is not being recognized or the anti-theft system has triggered. |
| Urgency | Stop - May Not Start |
🛑 What to Do When This Light Comes On
Step 1: Try your spare key first — the transponder chip in your primary key may have failed. If neither key works: disconnect the battery for 15 minutes to reset the system. If the light flashes rapidly while driving the immobilizer has lost signal — the car may stall.
⚠️ What happens if you ignore this light: If the immobilizer activates while driving the engine may shut off without warning. This is a safety risk. A failing ignition switch or key transponder is the most common cause.
🛠️ Technician's Notes: Common on vehicles with chip keys (virtually all cars after 2000). Aftermarket remote starters and key duplication can cause intermittent immobilizer faults.
📚 Data Sources: Warning light information compiled from SAE J2402 dashboard symbol standards, NHTSA vehicle safety regulations, OEM owner's manuals, and ASE master technician field experience. Different vehicle makes may display slightly different symbols. Always consult your owner's manual for make-specific warnings.