Knowledge base · Symptom & cause
Dashboard warning lights: what each symbol means
Modern cars have dozens of symbols and nobody knows them all by heart. Fortunately you don't need to: the colour already tells you how fast you must act. Below are the symbols that really matter.
Colour first, symbol second
- Red — act now. Stop safely, engine off, assess the situation. Driving on can cause damage or be dangerous.
- Amber/yellow — needs attention. You can usually drive on, but have it checked soon.
- Green/blue — information. Lighting, cruise control, main beam. Not a fault.
The symbols at a glance
| Light | Colour | What to do |
|---|---|---|
| Oil pressure (oil can) | Red | Stop immediately. Driving without oil pressure destroys the engine within minutes. |
| Coolant temperature | Red | Stop and let it cool. Only open the bonnet once the pressure is off. |
| Battery / charging | Red | The alternator is not charging. Drive straight to a garage; on battery power you won't get far. |
| Brake system | Red | Check the handbrake is off. If it stays on: do not drive on. |
| Airbag | Red | Airbags may not deploy in a collision. Have it read out; also a rejection point. |
| Engine management | Amber | Steady: have it read out. Flashing: stop. |
| ABS | Amber | Brakes still work, but without ABS control. Have it checked. |
| ESP / traction control | Amber | Flashing briefly while intervening is normal. Staying on means a fault. |
| Particulate filter (DPF) | Amber | Filter full. Drive a steady stretch, otherwise we regenerate it. |
| Tyre pressure | Amber | Check pressures, including for a slow puncture. |
| Glow plugs (diesel) | Amber | Normal on a cold start. Flashing afterwards means a glow system fault. |
| Power steering | Amber/red | Steering becomes heavy. Have it checked straight away. |
Three situations where people drive on too long
Red oil light. This is not a "top up the oil soon" signal but a pressure warning. Without oil pressure an engine seizes within minutes. Stopping costs you a tow; driving on costs you an engine.
Red temperature light. It often starts with a slowly rising gauge. Don't push on just to "make it home": an overheated engine can mean a warped cylinder head.
Battery light. This is not about the battery but about the charging system. Drive on and everything runs off the battery: first the lights, then the engine management. More in car won't start: battery, alternator or starter.
What we do after a warning
We read out all control units, not just the engine — an ABS or airbag light sits in a different system. Then we assess the measured values and look for the cause, instead of clearing the code and hoping. How that works is in car diagnostics explained.
A fault like this belongs with brand-specific diagnostics in Tilburg, not a plain OBD scan.