Brake warning light: causes and what to check
The red brake light (an exclamation mark inside a circle) covers three very different things: the parking brake being applied, low brake fluid, or a hydraulic circuit fault.
Stop or act now — a safety or mechanical risk
Rule out the parking brake first. If it stays on with the brake fully released, treat it as urgent and stop driving.
Only after confirming the parking brake is fully released and the fluid level is correct. A brake light with a firm, normal pedal and correct fluid is less serious than one with a soft or sinking pedal — that combination means stop.
Common causes
- Parking brake not fully released, or a sticking release switch
- Brake fluid below the minimum mark, often from worn pads lowering the level
- Leak in a brake line, hose, caliper or the master cylinder
- Faulty brake fluid level sensor in the reservoir cap
- On many cars, a shared lamp with an ABS or EBD fault
What to do next
- 1Release the parking brake fully and see whether the light goes out.
- 2Check the fluid reservoir level; top up only with the fluid specification printed on the cap.
- 3Press the pedal — if it feels soft, spongy or sinks slowly, do not drive.
- 4Look for damp patches or fluid on the inside of the wheels and under the car.
- 5If the level was low, find out why: pads at the end of their life or a genuine leak.
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Ask the AI mechanicFrequently asked
- Why does the brake light come on only when cornering?
- That usually means the fluid is close to the minimum mark and the level sensor is being uncovered as the fluid moves in the reservoir. Check the level and pad thickness.
- Can worn brake pads cause the light?
- Yes, indirectly. As pads wear, caliper pistons extend and hold more fluid, so the reservoir level drops. Some cars also have a separate pad-wear warning.
General guidance only. Symbols and thresholds vary between manufacturers — always confirm against your vehicle's owner manual, and treat any red lamp as a reason to stop.
Other dashboard lights
- Check engineThe check engine light (an engine-block outline, usually amber) means the engine management system has stored a fault code. Steady means investigate soon; flashing means stop driving.
- Oil pressureThe red oil-can symbol means the engine has lost oil pressure. This is the most serious light on the dashboard — continued driving can destroy the engine in under a minute.
- ABSThe amber ABS lamp means the anti-lock braking system has disabled itself. Normal braking still works, but the wheels can lock under hard or emergency braking.
- Battery / chargingThe red battery symbol means the charging system is no longer supplying enough voltage. The car is running on stored battery charge and will eventually stop.
- Coolant temperatureA red thermometer symbol means the engine is overheating. Continued driving risks a warped head, failed head gasket or a seized engine.
- Tyre pressure (TPMS)The amber horseshoe with an exclamation mark means at least one tyre is significantly below its target pressure — or the monitoring system itself has a fault.
- Airbag / SRSThe SRS or airbag symbol means the supplementary restraint system has detected a fault and has disabled itself. In a crash, the airbags or pretensioners may not fire.
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