Dashboard warning lights can be confusing, and it is tempting to ignore one that comes on when the car still seems to drive fine. The trouble is that some lights are urgent safety warnings. Here is a plain English guide to the main ones and what to do.
The colour is your first clue
As a general rule, red means stop safely and act now, amber or orange means get it checked soon, and green or blue is simply information, such as your lights being on. When a red light appears, take it seriously.
Red: act now
- Oil pressure. An oil can symbol in red means low oil pressure. Stop as soon as it is safe, because running on low pressure can wreck the engine.
- Engine temperature. A thermometer symbol means the engine is overheating. Pull over, switch off and let it cool, do not keep driving.
- Brake warning. This can mean low brake fluid or a fault. Treat any brake warning as urgent.
- Battery or charging. If the battery light stays on while driving, the charging system may have a fault and the car could stop once the battery drains.
Amber: check soon
- Engine management light. This covers a wide range of faults, from a loose fuel cap to a sensor or emissions problem. The car may drive normally, but it should be plugged in and read properly to find the cause.
- ABS. Your normal brakes still work, but the anti lock system may not, so get it checked.
- Tyre pressure. One or more tyres may be low. Check and inflate, and look for a puncture.
- Glow plug (diesel). A coil symbol that stays on can point to a fault worth checking.
Why a light can mean an MOT fail
Some warning lights, such as airbag, ABS, brake and the engine management light, can cause an MOT failure if they stay illuminated. Sorting them before your test saves a wasted trip. You can read more on our MOT page.
What to do when a light appears
Check your handbook to identify the exact symbol, note whether it is steady or flashing, and whether the car feels different. A flashing engine light in particular means ease off and get it looked at quickly. If in doubt, it is always safer to have it diagnosed than to guess.
If a warning light has appeared and you are not sure what it means, bring the car to us. A proper diagnostic read takes the guesswork out and tells you exactly what needs doing. See our services page or get in touch.
Book with your local Guildford garage
SMA Autos LTD is an independent garage in Normandy, Guildford, looking after drivers across Guildford, Worplesdon, Ash, Pirbright, Fairlands and the wider Surrey area. For honest advice and a clear price before any work starts, book online or call us on 07921 814250.