Dashboard Warning Lights Explained: What They Mean and What to Do
Car Owl
Published in English •
Summary
- Red lights mean stop: Pull over safely and investigate immediately.
- Amber/yellow lights mean caution: Something needs attention soon, but you can usually keep driving.
- Green/blue lights are informational: Just telling you a system is active.
Dashboard warning lights can be scary. But understanding what they mean helps you react correctly — and could prevent serious damage or danger.
Here's a guide to the most important warning lights and what to do when they appear.
Red Warning Lights — Act Immediately
Red means the problem is serious. Pull over when safe and check the issue.
| Light | What It Means | What to Do |
|---|---|---|
| Engine temperature | Engine is overheating | Stop immediately. Let the engine cool. Check coolant level. Do NOT open the radiator cap when hot. |
| Oil pressure | Oil pressure is dangerously low | Stop immediately. Check oil level. Do not drive until resolved — engine damage is likely. |
| Battery | Charging system failure | Battery isn't charging. Drive to a garage soon. Turn off non-essential electrics to conserve power. |
| Brake system | Brake fault or handbrake on | Check handbrake is fully released. If light stays on, brake fluid may be low or there's a system fault. |
| Airbag | Airbag system fault | Airbags may not deploy in a crash. Get it diagnosed as soon as possible. |
| Power steering | Power steering failure | Steering will be very heavy. Drive carefully to a garage. |
Amber/Yellow Warning Lights — Attention Needed
Amber lights mean something needs checking, but it's usually safe to continue driving for now.
| Light | What It Means | What to Do |
|---|---|---|
| Engine management (check engine) | Engine sensor fault | Book a diagnostic check. Could be minor (sensor) or major (catalytic converter). Will fail the MOT. |
| ABS | Anti-lock braking system fault | Normal brakes still work, but ABS may not function. Get checked soon. |
| Tyre pressure (TPMS) | One or more tyres are low | Check tyre pressures and inflate to the correct level. Could indicate a slow puncture. |
| DPF (diesel) | Diesel particulate filter blocked | Take a 20-30 minute motorway drive to regenerate the DPF. If light stays on, get it checked. |
| Traction control / ESP | Stability system active or fault | If flashing, the system is working. If solid, there may be a fault. Drive carefully. |
| Fuel level | Running low on fuel | Fill up soon. Most cars have 30-50 miles left when the light comes on. |
Green and Blue Lights — Information Only
- Indicators (green): Your indicator is on.
- Cruise control (green): Cruise control is active.
- Full beam (blue): Full beam headlights are on. Dip them for oncoming traffic.
- Eco mode (green): You're driving in an eco-efficient way.
These lights don't indicate a problem. They're just telling you what's switched on.
When to Go to a Garage
- Any red light: Get it checked immediately. Don't keep driving unless it's safe.
- Engine management light: Book a diagnostic as soon as possible. It could be a £50 sensor fix or something more serious.
- Multiple lights at once: If several warning lights come on together, stop driving and call a mechanic or breakdown service.
Check your MOT history to see if related issues have been flagged in previous tests.
How Much Does a Diagnostic Check Cost?
A basic diagnostic check (plugging in a code reader) costs £30-£75 at most garages. Some offer free diagnostics with a repair.
The code tells the mechanic which system triggered the warning light. It doesn't always mean something expensive is wrong.
Warning lights exist to protect you and your car. Never ignore a red light, and don't put off investigating amber warnings. A quick diagnostic check can catch small problems before they become big — and expensive — ones.
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