What this warning means
A warning light identifies a system, condition, or protection strategy. It does not authorize a parts replacement by itself.
A warning lamp signals a condition or protection strategy. Its color, behavior, messages, and companion symptoms control urgency.
- 01IdentifyMIL · assess urgency
- 02AssessIf the lamp is flashing, the engine is shaking badly, or power is dropping, reduce load and stop safely. If it is steady
- 03PreserveCode and module that set it / Freeze-frame or event data
- 04CheckNote whether the lamp is steady or flashing and whether the engine is running unevenly. / Scan all supported modules and preserve codes plus freeze-frame data before clearing them.
- 05VerifyFollow the vehicle source and confirm the warning stays resolved
Follow the sequence, stop when evidence changes the path, and verify the exact vehicle information before acting.
Record the exact symbol, color, steady-versus-flashing behavior, messages, and other lamps before clearing evidence.
Safe first checks
Note whether the lamp is steady or flashing and whether the engine is running unevenly.
Use the vehicle's owner/service information when the check depends on a location, specification, service mode, or scan-tool function.
Scan all supported modules and preserve codes plus freeze-frame data before clearing them.
Use the vehicle's owner/service information when the check depends on a location, specification, service mode, or scan-tool function.
Record fuel level, recent repairs, operating temperature, load, and when the lamp appeared.
Use the vehicle's owner/service information when the check depends on a location, specification, service mode, or scan-tool function.
Use the code as a starting direction; test the system and circuit before replacing a part.
Use the vehicle's owner/service information when the check depends on a location, specification, service mode, or scan-tool function.
Evidence worth preserving
Code and module that set it
Freeze-frame or event data
Cold-versus-hot behavior
Misfire, fuel-trim, temperature, or drivability changes
Can you keep driving?
Safety boundary
Flashing or severe symptoms change the urgency
Do not continue normal driving when the indicator flashes or the engine is shaking, overheating, losing power, or producing a strong fuel odor.