Evidence grade: B1 — Trade practice Effort: N/A — reference, no procedure
Answer: color is your first-pass urgency cue — red means stop or check now, amber means schedule service soon, green/blue/white means a system is on or working. Exact symbols and required actions vary by make and model; your owner's manual is the final word. This decoder is drawn from owner's-manual-sourced explanations and covers the lights you'll actually meet [1].
| Light | Color | What it means | What to do |
|---|---|---|---|
| Check engine | Amber (solid) | The computer stored a fault — can be anything from a loose fuel cap to a sensor failure | Schedule service soon; an OBD-II scan will tell you which [1] |
| Check engine | Flashing | Serious condition (often misfire) that can damage the emissions system | Reduce speed and load; drive gently to the nearest service point [1] |
| Oil pressure | Red | Oil pressure lost — the engine is starving for lubrication | Pull over safely and shut the engine off immediately; tow it [1] |
| Coolant temperature | Red | Engine overheating | Pull over, shut off, let it cool — never open a hot radiator cap (scalding) [1] |
| Charging system (battery) | Red | Battery is not charging — the alternator or electrical system has failed | Get to a shop before the battery dies; the car can stall [1] |
| Brake warning | Red | Parking brake engaged — or, with the parking brake released, low brake fluid or a brake-system fault | Check the parking brake first; if the light stays on, get brakes inspected immediately [1] |
| TPMS (tire pressure) | Amber | One or more tires is low | Check and inflate to the door-jamb pressure |
| Traction/stability control | Amber (flashing) | System is actively intervening (normal in a skid); steady on = system fault | If steady, schedule service |
Things that are normal
- Several lights flash on at startup and then go out. That's the self-test — each warning circuit checking itself. Only lights that stay on are telling you something [1].
- A steady amber light that clears after a few drive cycles (e.g., after a loose gas cap is tightened) can resolve itself; if it persists, scan it.
- Green, blue, or white indicators (cruise control, high beams, lane assist) are status, not warnings.
Honest limits
- This decoder was compiled from owner's-manual-derived sources for one manufacturer's lineup — symbols, colors, and required actions differ across brands and years, so confirm against your manual before acting [1].
- A warning light names the system, not the cause: a check-engine light can be a $20 gas cap or a failing catalytic converter — only a scan (or a mechanic) tells you which.
- EVs and hybrids add lights (battery, charging, high-voltage) that this table doesn't cover; their manuals are mandatory reading.
Sources
- Dunn Ram Trucks — "Dash Warning Lights Ram Jeep Explained" (meanings drawn from Ram/Jeep owner's manuals). https://www.dunnramtrucks.ca/blog/dash-warning-lights-ram-jeep-explained/ — red = pull over or address immediately (oil pressure: shut engine down; coolant: pull over, never open hot cap; brake: with parking brake released, inspect now); charging-system light = battery not charging; flashing check engine = serious, reduce load and seek immediate service; steady amber = stored fault, service soon; several lights at startup = normal self-test; green/blue/white = active systems, not warnings.
Repair Lab · Release 1 · Evidence last checked September 30, 2026 · A project of AOJEL