Use the Motor Vehicle Expert Warning Light Checker
Before reading every guide, you can use the free diagnostic app page to check common dashboard warning lights, safe-to-drive guidance, possible causes, next checks and MOT implications.
Check severity
Understand whether the warning may be low, medium or high urgency.
Safe to drive?
Get plain-English guidance on whether you should stop, drive carefully or book diagnosis.
MOT impact
See whether warning lights may affect MOT results, especially safety and emissions systems.
Next checks
Find sensible first checks before guessing parts or spending money.
What should you do when a warning light appears?
Red lights, flashing lights, brake warnings, oil pressure warnings, overheating, charging faults and steering warnings usually need faster attention.
A warning light should be judged by its colour, whether it is steady or flashing, and how the car feels.
Amber lights often mean the car has detected a fault but may still drive. That does not mean they should be ignored. If the car loses power, overheats, smokes, shakes, struggles to brake or becomes hard to steer, stop safely and arrange inspection.
Common dashboard warning light guides
Start with the warning light you can see, then check whether the car has changed how it drives, brakes, steers, starts or accelerates.
Diagnostic App Warning Light Lookup
Check warning light severity, safe-to-drive guidance, possible causes and MOT implications.
Use warning light checker →Car Warning Lights Meaning UK
A broader guide to dashboard symbols and what to check first.
Read full guide →Engine Management Light Explained
What the engine management light can mean, common causes and when the issue may be serious.
Read guide →Can You Drive With Engine Management Light On?
Steady vs flashing engine light, safe driving advice and when to stop driving.
Read guide →Will Engine Management Light Fail MOT?
When an engine warning light can affect an MOT and what to do before the test.
Read guide →Battery Warning Light Meaning
Charging system faults, alternator problems, belt issues and poor electrical connections.
Read guide →Oil Warning Light On and Off
Oil pressure, oil level, sensors and when oil warnings may make driving unsafe.
Read guide →Brake Warning Light On While Driving
Low brake fluid, handbrake faults, braking problems and when to stop immediately.
Read guide →ABS Warning Light On: Is It Safe to Drive?
Common ABS warning causes, braking safety advice and what to check next.
Read guide →Airbag Warning Light MOT Failure UK
Whether an airbag warning light can fail an MOT and why safety faults matter.
Read guide →DPF Warning Light Explained
Diesel particulate filter warnings, regeneration, limp mode and when to act sooner.
Read guide →EPC Warning Light Meaning UK
What the EPC light means, common causes and whether it is safe to keep driving.
Read guide →Power Steering Warning Light Meaning
Power steering warning causes and when steering assistance may be affected.
Read guide →Tyre Pressure Warning Light Reset UK
Why the TPMS light comes on, what to check first and how reset systems work.
Read guide →Traction Control Light On But Car Drives Fine
Why traction control warnings can appear even when the car still feels normal.
Read guide →Service ESC Light Meaning
What a service ESC warning can mean and when stability control faults need checking.
Read guide →Service Light On After Service
Why a service light may stay on after maintenance and what to check first.
Read guide →What warning light colour usually means
Red warning light
Usually more urgent. Red lights often relate to safety, braking, oil pressure, overheating, charging or systems that may make the car unsafe.
Amber or yellow warning light
Usually means a fault needs attention soon. The car may still drive, but the system has detected a problem.
Green or blue light
Often means a system is active, such as lights or main beam, rather than a fault.
A flashing warning light is usually more urgent than a steady one. For example, a flashing engine management light can point to a misfire or emissions damage risk.
Warning lights you should not ignore
Some lights can point to faults that affect safety or engine damage risk. These should be treated more seriously, especially if the car also feels different.
Oil pressure warning
Low oil pressure can damage an engine quickly. Stop safely and check guidance.
Oil warning guide →Brake warning light
Brake fluid, braking system faults or handbrake problems may need urgent attention.
Brake warning guide →Battery warning light
A charging fault can leave the car unable to run or restart.
Battery warning guide →Flashing engine light
A flashing engine light can indicate a more serious engine or emissions fault.
Flashing engine light guide →Power steering warning
Loss of steering assistance can make the car much harder to control.
Steering warning guide →Airbag warning light
Airbag or restraint system faults can affect crash protection and MOT results.
Airbag warning guide →Warning light plus symptoms: what it may suggest
Warning light with power loss
Power loss can point towards limp mode, turbo faults, DPF problems, fuel delivery issues, engine management faults or sensor problems.
Power loss guide →Warning light with shaking or misfire
Engine shaking, rough idle or jerking with a warning light can suggest misfire, ignition, fuel or engine-running faults.
Misfire guide →Warning light with overheating
Rising temperature, steam or coolant warnings need quick action because overheating can damage the engine.
Overheating guide →Warning light with poor starting
Starting problems can involve the battery, alternator, starter motor, immobiliser, fuel system or engine sensors.
No-start diagnosis →Engine, emissions and diesel warning lights
Engine and emissions warnings can be confusing because the car may still drive normally at first. The key is whether the light is steady or flashing, whether power is reduced and whether there is smoke, rough running or poor fuel economy.
Engine management light
Sensors, misfires, emissions faults, fuel mixture and engine control issues.
Read guide →DPF warning light
Diesel particulate filter soot loading, regeneration problems and limp mode.
Read guide →EPC warning light
Throttle, engine control, brake switch and sensor faults on many VW-group cars.
Read guide →If the warning light involves the battery or charging system
Battery lights are often about charging, not just the battery itself. A failing alternator, slipping belt, poor earth or weak battery can all cause warnings and eventually leave the car unable to restart.
Alternator Not Charging Battery Signs
Dim lights, flat battery, dashboard warnings and charging output problems.
Read guide →Alternator Replacement Cost UK
Typical alternator replacement prices and what affects the final cost.
Read guide →How To Check Car Battery Health
Weak battery symptoms, starting issues and basic checks.
Read guide →Car Battery Keeps Going Flat
Battery drain, alternator faults, short trips and old battery issues.
Read guide →Battery Light On After New Battery
Why the battery warning may stay on even after fitting a new battery.
Read guide →Car Won’t Start But Battery Seems Fine
Starter, immobiliser, ignition and fuel faults that can feel battery-related.
Read guide →Brake, ABS, airbag and safety-system warnings
Safety-system warning lights matter because they may affect braking stability, crash protection, steering assistance or vehicle control systems. Even if the car feels normal, these faults should be checked.
Brake warning light
Low brake fluid, handbrake issues, braking system faults or hydraulic concerns.
Read guide →ABS warning light
ABS may not work during emergency braking, even if normal braking remains.
Read guide →Airbag warning light
SRS faults can affect restraint systems and MOT results.
Read guide →Power steering warning
Steering may become heavier or assistance may be reduced.
Read guide →Traction control warning
Stability or traction systems may be disabled or limited.
Read guide →ESC warning
Electronic stability control faults should be checked, especially before MOT.
Read guide →Can warning lights affect an MOT?
Yes. Some dashboard warnings can affect MOT results, especially if they relate to emissions, brakes, airbags, ABS, ESC, TPMS or other mandatory safety systems.
Engine management light
Can fail an MOT, especially where emissions are affected.
Read guide →ABS light
ABS warning lights can fail where the system indicates a fault.
Read guide →Airbag light
Airbag warning lights can fail because they relate to occupant safety.
Read guide →Tyre pressure light
TPMS warnings can affect MOT results on vehicles where the system is required.
Read guide →Traction control light
Traction or stability control warnings may affect MOT outcome.
Read guide →Common MOT failures
Lights, tyres, brakes, suspension, visibility and emissions issues.
Read guide →What to do when a warning light appears
1. Check the colour
Red warnings usually need faster action than amber warnings.
2. Notice symptoms
Power loss, overheating, smoke, brake changes or steering changes make the issue more urgent.
3. Use the app
The diagnostic app page can help you check possible causes, safe-to-drive guidance and MOT implications.
Open diagnostic app →4. Check the handbook
Symbols vary by manufacturer, so confirm the meaning for your vehicle.
5. Read fault codes
Fault-code reading helps identify the affected system, but codes still need interpretation.
6. Fix the cause
Clearing the warning without repairing the fault usually means it will return.
Warning light mistakes to avoid
- !Ignoring a red light because the car still drives.
- !Clearing fault codes without fixing the cause.
- !Assuming a battery light means only the battery is faulty.
- !Driving with an oil pressure warning.
- !Leaving warning lights until MOT day.
- !Buying a used car with warning lights on without diagnosis.
Related diagnostics and maintenance guides
Frequently asked questions
Can I keep driving with a warning light on?
It depends on the light and symptoms. Red, flashing, brake, oil pressure, overheating, charging or steering warnings need more urgent attention.
Does a warning light always mean an expensive repair?
No. Some faults are simple, but diagnosis is needed before guessing at parts.
Can a warning light fail an MOT?
Yes. Some lights can affect MOT results, especially airbag, ABS, engine/emissions, TPMS and safety-system warnings.
What does an amber warning light mean?
An amber warning usually means a fault needs attention soon. The car may still drive, but it should not be ignored.
What does a red warning light mean?
A red warning usually means stop safely or act urgently, especially if it relates to brakes, oil pressure, overheating, steering or charging.
Is a flashing warning light serious?
Usually yes. A flashing warning light is normally more urgent than a steady one and should be checked quickly.