The different warning lights on your vehicle
A light comes on on the dashboard, and the same little worry kicks in: is it serious? Should you stop straight away, or can you finish your journey calmly? Good news: these warning lights follow a simple logic. Once you know the colour code and the most common lights, you immediately know how to react. Here is our guide to help you see clearly.
A colour code worth knowing by heart
All manufacturers use the same principle, borrowed from traffic lights. The colour of the warning light tells you how urgent it is before you even know exactly what it means.
Red: stop. A red light signals a serious problem, possibly dangerous for you or your engine. The rule is simple: stop as soon as it is safe to do so, then switch off the engine.
Orange (or yellow): stay alert. An orange light signals a fault or upcoming maintenance. You can usually keep driving, but have the vehicle checked without delay. It is not an absolute emergency, but it should not be ignored either.
Green and blue: all is well. These lights are purely informative. They confirm that a system is active (your lights, your indicator, your cruise control). No action is needed on your part.
Red warning lights: never ignore them
These are the most important. If they come on while you are driving, take them seriously.
The oil pressure warning light (an oil can) indicates that the engine is no longer properly lubricated. It is one of the most critical: continuing to drive can destroy the engine in a few minutes. Stop immediately.
The temperature warning light (a thermometer in waves) signals that the engine is overheating. Switch off the engine and let it cool down before touching anything.
The battery or charging warning light (a small battery) means that the alternator is no longer charging the electrical system properly. The vehicle may stop once the battery runs flat.
The brake warning light can indicate a low fluid level, a brake pad problem or simply that the handbrake is still on. Check it first, as your braking safety is at stake.
The airbag warning light signals a fault in the passive safety system. The airbags might not deploy in a collision.
Orange warning lights: have them checked without delay
Less alarming, they still deserve your attention.
The engine warning light (the outline of an engine) is probably the best known and the broadest: it covers many faults, from a defective sensor to an injection problem. Only an electronic diagnosis can identify the exact cause.
The ABS warning light signals a fault in the anti-lock braking system. Normal braking still works, but emergency braking assistance is no longer guaranteed.
The ESP/ASR warning light relates to stability control and traction control. If it flashes, the system is working; if it stays on, it has a fault.
The tyre pressure warning light alerts you to a loss of pressure in one or more tyres. Check it quickly for your safety and to limit tyre wear.
The glow plug warning light (a coiled spring), specific to diesel engines, is normal for a few seconds when starting from cold. If it stays on or flashes, it is a sign of a fault.
The diesel particulate filter (DPF) warning light, also specific to diesels, indicates that the filter is clogged. A drive at sustained speed is sometimes enough to regenerate it; otherwise, a visit to the workshop is needed.
Green and blue warning lights: simply informative
No need to worry about these. Green confirms that a piece of equipment is working: dipped headlights, indicators, cruise control. Blue almost always signals that your high beams (full headlights) are on. They are part of your vehicle’s normal operation.
What should you do when a warning light comes on?
Keep three simple reflexes in mind:
- Identify the colour. Red: stop safely; orange: schedule a check; green or blue: carry on calmly.
- Never push on with a red light. It is better to stop than to risk costly engine damage or an accident.
- Get a diagnosis. Many warning lights, especially the engine light, only reveal their exact cause with an electronic diagnostic tool.
Unsure about a warning light? Garage RR is here for you
In Ecublens, Garage RR carries out an electronic diagnosis of your vehicle and clearly explains what to do next. Rather than staying in doubt or risking a bigger repair, come and see us as soon as a warning light worries you. A quick check is always better than a breakdown on the road.
Contact Garage RR in Ecublens to book an appointment.
