Red warning lights mean stop as soon as it's safe. Amber lights mean something needs checking soon. Here are the ten you're most likely to see, what each usually means, and whether you can keep driving. Your handbook has the final word for your vehicle.
Instrument cluster
Red means stop when it's safe. Amber means book it in soon. Your handbook has the final word for your vehicle.
Tap the symbol you can see. You'll get what it usually means, whether it's safe to keep driving, and a one-tap WhatsApp to D&R.
Amber: get it checked
What it means: The engine computer has stored a fault. It could be a sensor, the ignition, the fuel system or emissions.
Can I keep driving? Steady and driving normally: get it checked soon. Flashing: ease off and stop when safe, it usually means a misfire that can damage the catalytic converter.
What D&R does: D&R reads the fault codes and tests the parts involved to find the cause.
Red: stop when it's safe
What it means: Oil pressure is too low to protect the engine. Often the oil level is low, sometimes the pump or a sensor has failed.
Can I keep driving? Stop as soon as it's safe and switch off. Running an engine without oil pressure can destroy it within minutes. Check the level once the engine is cool and don't drive on with the light lit.
What D&R does: D&R checks the oil level and leaks, the pressure sensor and its wiring, and the oil pump to find why the pressure dropped.
Red: stop when it's safe
What it means: The charging system isn't charging. Usually the alternator, the drive belt or the wiring, not the battery itself.
Can I keep driving? The car is running on what's left in the battery. It may cut out, so head somewhere safe and avoid switching off.
What D&R does: D&R tests the battery, alternator and belt to find which part has failed.
Red: stop when it's safe
What it means: The engine is overheating or the coolant level is low.
Can I keep driving? Pull over and switch off. Never open the coolant cap while it's hot: the system is under pressure. Let it cool before going any further.
What D&R does: D&R finds the leak or the failed part, from hoses and the radiator to the water pump, thermostat and fan.
Red: stop when it's safe
What it means: The handbrake is on, the brake fluid is low, or the brake system has a fault.
Can I keep driving? If it stays on with the handbrake off, don't drive. Low fluid can mean a leak.
What D&R does: D&R checks the fluid, pads, hoses and system for the cause.
Amber: get it checked
What it means: The anti-lock braking system has a fault, often a wheel speed sensor or its wiring.
Can I keep driving? Normal braking still works, but the wheels can lock under hard braking. Leave more room and book it in.
What D&R does: Diagnostic testing finds which sensor or part has failed.
Amber: get it checked
What it means: On a diesel it lights briefly when you switch on. If it flashes while driving, many diesels use it to show an engine fault.
Can I keep driving? If it flashes while driving, the car may go into limp mode. Get it diagnosed.
What D&R does: D&R reads the codes and checks glow plugs, sensors and the fuel system.
Amber: get it checked
What it means: The diesel particulate filter is getting blocked with soot, usually from lots of short journeys.
Can I keep driving? A steady run at higher speed often lets it clear itself (check your handbook). If it stays on, book it in.
What D&R does: D&R diagnoses the cause, from sensors to EGR faults, before the filter blocks completely.
Red: get it checked soon
What it means: There's a fault in the airbag or seatbelt tensioner system.
Can I keep driving? The car drives normally, but the airbags may not work in a crash. Get it checked soon.
What D&R does: D&R reads the airbag system fault codes to find the cause.
Amber: get it checked
What it means: The power steering has a fault. Steering assistance may be reduced or gone.
Can I keep driving? The steering may suddenly feel heavy. Drive carefully and book it in.
What D&R does: D&R checks the steering system, fluid and electrics for the fault.
The WhatsApp message is already written for you. Add the reg and what's going on, then send it.