How to read what your car is telling you

Most cars give plenty of warning before something goes seriously wrong. The trick is knowing which signals mean book a service now, and which mean carry on driving until next month. Here are eight of the clearest, most common signs your car is overdue.

1. The check engine light

The amber engine-shaped light is the dashboard's most-ignored warning. It means the car's onboard computer has logged a fault code in the engine or emissions system. Sometimes the cause is small (a loose fuel cap on some models). Sometimes it points to a misfire, a failing oxygen sensor, or a catalytic converter on its way out.

The car will usually still drive. That is not a reason to leave it. A diagnostic scan takes minutes and tells you exactly what the fault is. Book a car diagnostic in Worthing if the light comes on.

2. The low oil warning light

A red oil-can light means oil pressure has dropped. Pull over as soon as it is safe and switch off. Driving on with low oil pressure can destroy an engine in minutes.

If it is an amber light (low oil level), the engine still has pressure but the level is below the minimum mark. Top up with the correct oil for your car and book a service to find out why the level dropped. Burning, leaking, or just overdue.

3. Tyre pressure warning

The TPMS (tyre pressure monitoring system) warns when one or more tyres are below the safe pressure. Most modern cars have it as standard. Check all four pressures cold and reset the system once corrected. If the light comes back, you have a slow puncture or a faulty sensor.

4. Other dashboard warning lights

Modern cars have warning lights for ABS, traction control, airbag, glow plugs, DPF, AdBlue, electronic parking brake and more. The colour is the priority:

  • Red = stop as soon as safe, do not drive on.
  • Amber = book a check in the next few days, but the car is safe to drive.
  • Green or blue = informational, no action needed.

Any red light is a reason to call a garage rather than drive. A scan tool reads the fault codes so the garage knows what is going on before you arrive.

5. A whining sound from under the bonnet

Whining usually comes from a belt-driven component (alternator, power steering pump, water pump) or the gearbox in some cases. The sound rising and falling with engine speed points to the belt or one of the pulleys. Whining that rises with road speed points to the gearbox or differential.

None of those need an immediate stop, but they all need looking at. A worn alternator bearing can fail and strand you. A power steering whine can become heavy steering overnight.

6. Unusual engine noise at idle

A healthy modern engine is almost silent at idle. New noises matter:

  • Ticking = often valve clearances or low oil pressure.
  • Rumbling or rattling = often a worn timing chain, especially on petrol VAG, BMW and Ford EcoBoost engines.
  • Hissing = vacuum or boost leak.
  • Knocking = serious. Get it checked before driving further.

7. Grinding metal when braking or turning

Grinding when braking means the brake pads have worn through to the metal backing plate, and the pad is now eating into the disc. Pads are inexpensive, discs are not. Book it the same week.

Grinding when turning at low speed (especially in a tight car park) is often a worn CV joint. Drive carefully and book a check.

8. Squealing brakes

A high-pitched squeal at light braking is usually a wear indicator built into the brake pad. It is designed to make a noise when the pad gets thin so you know to book a brake check.

Squealing only on first use in the morning, then fading, is normal on cold damp pads. Squealing that gets worse with use is not.

What to do next: book a service

If any of these signs apply to your car, the next step is a service. A full or interim service catches the underlying cause early, before the warning becomes a breakdown.

Book a car service in Worthing, or read more: