Dashboard warning lights: what they mean
A light just came on. Here is what each one means, how urgent it is and what to do next. Symbols vary a little between makes, so your owner's manual has the exact one for your car.
- Pull over safely
- Get it checked today
- Book this week
Rule of thumb: a red light means stop and deal with it now. A yellow or amber light means get it checked soon. A flashing light of either colour is more urgent than a steady one.
Check engine
Book this weekThe engine computer has stored a fault. Steady light: the car is usually fine to drive to the shop. Flashing light: the engine is misfiring, so ease off and get it in right away.
What to do: Note whether it is steady or flashing and how the car feels, then book a diagnostic.
A steady check engine light covers hundreds of possible faults, from a loose gas cap to a failing sensor or a vacuum leak. The car stores a code that points to the system involved.
A flashing light means an active misfire. Unburned fuel is going into the exhaust and can overheat the catalytic converter, which is an expensive part. Reduce speed, avoid hard acceleration and have it looked at before driving any distance.
Oil pressure
Pull over safelyThe engine is not getting proper oil pressure. Running it can destroy the engine in minutes.
What to do: Pull over, switch the engine off and check the oil level. Do not keep driving with this light on.
This red oil can is about pressure. It is different from a yellow oil level or oil change reminder. Low pressure means the moving parts inside the engine are not being lubricated.
If the dipstick shows the level is low, topping up may put the light out, but the reason it was low still needs finding. If the level is fine and the light stays on, have the car towed.
Engine temperature
Pull over safelyThe engine is overheating. Driving on can warp the cylinder head or blow the head gasket.
What to do: Pull over, switch off and let it cool. Never open the radiator or coolant cap while it is hot.
Common causes are low coolant from a leak, a failed water pump, a stuck thermostat or a cooling fan that is not running.
Once it has fully cooled you can check the coolant level in the overflow tank. Even if topping up gets you moving, the leak or failed part is still there.
Brake system
Pull over safelyCheck the parking brake is fully released first. If the light stays on, the brake fluid may be low or the system has a fault.
What to do: If the pedal feels soft, sinks or the car takes longer to stop, do not drive it. Call us.
Brake fluid drops as pads wear, and it also drops when there is a leak. Either way a red brake light that stays on needs a proper look before the car is driven far.
On many European cars a separate yellow light means the pad wear sensor has been reached. That one is a reminder to book a brake job soon.
Battery / charging
Get it checked todayThe alternator has stopped charging the battery. The car is running on stored power and will stall when it runs out.
What to do: Turn off what you can (heated seats, rear defrost, stereo) and drive straight to a shop.
Usual causes are a failed alternator, a broken or slipping drive belt, or a bad connection at the battery. On many engines that same belt also drives the water pump, so watch the temperature gauge.
Tire pressure
Get it checked todayOne or more tires is low. Steady light: check and set the pressures. Flashing then steady: a sensor has a fault.
What to do: Check all four tires against the sticker in the driver's door jamb. If one keeps losing air, it likely has a puncture.
Pressures drop as the weather gets colder, so this light often shows up on the first cold mornings of fall. If the light returns after you set the pressures, a tire is leaking.
A light that flashes for about a minute at start-up and then stays on points to the monitoring system itself, often a sensor with a dead battery.
ABS
Book this weekThe anti-lock system is switched off because of a fault. Normal braking still works, but the wheels can lock in a hard stop.
What to do: Leave extra room, especially in rain or snow, and book a diagnostic.
The most common cause is a wheel speed sensor or its wiring, which lives in a harsh spot behind the wheel. Traction and stability control usually switch off with it, so those lights may come on too.
Airbag (SRS)
Book this weekThe airbag system has found a fault. Airbags or seat belt pretensioners may not work in a crash.
What to do: The car drives normally, but have it scanned soon. This light does not clear on its own.
Common causes are a seat occupancy sensor, a connector under the seat or the clock spring behind the steering wheel. The system has its own codes that need a scan tool to read.
Power steering
Get it checked todaySteering assist has a fault. The wheel can become very heavy, mostly at low speed.
What to do: You can still steer, with effort. Drive carefully to a shop and avoid tight parking manoeuvres.
Older systems are hydraulic, so low fluid or a leak is the usual cause. Most newer cars use an electric motor, where the fault can be the motor, a sensor or low system voltage.
Traction / stability
Book this weekFlashing while you drive on a slippery road is normal: the system is working. Staying on means it has a fault or has been switched off.
What to do: Check you did not press the off button. If it stays on, book a diagnostic.
This system shares its sensors with the ABS, so a wheel speed sensor fault often lights both. A steering angle sensor that needs recalibrating is another common cause after suspension or alignment work.
Not sure what the light means?
Send us a photo of your dash by text. We will tell you what it is and how soon it needs looking at.