Can My Car Fail Its MOT for Warning Lights?

You’re driving along and suddenly — ping! — a warning light flashes up on your dashboard. Maybe it’s the engine icon, an ABS symbol, or even a light you’ve never seen before. It might be tempting to ignore it, especially if the car feels fine… but when your MOT is due, that little light could turn into a big red flag.

So the question is: can your car fail its MOT just because of a dashboard warning light?

Short answer? Yes. And here’s everything you need to know to avoid it.

? Dashboard Lights & the MOT — The Basics

The MOT test (Ministry of Transport) is a legal requirement in the UK for most vehicles over 3 years old. It assesses the roadworthiness, safety, and environmental standards of your car. Since 2018, the rules around dashboard warning lights have become stricter — meaning your car can fail automatically if certain lights are on during the test.

Which Lights Can Cause a Fail?

The MOT manual categorises faults into Minor, Major, and Dangerous. Certain warning lights fall into the Major or Dangerous categories, resulting in an immediate fail.

Some of the most common lights that can fail your MOT include:

• Engine Management Light (EML)

• ABS Warning Light

• Airbag/SRS Warning Light

• Brake System Warning Light

• Power Steering System Light

• Tyre Pressure Monitoring System (TPMS) Light (for cars registered after January 2012)

? Learn more about common warning lights and what they mean

What If It’s Only an Intermittent Light?

If the light goes off during the test and doesn't return, you may pass. But if the light is on when the ignition is in the 'on' position or stays on once the engine is running, it will be recorded and may cause failure.

? Why These Lights Matter — Legal and Safety Insight

Dashboard lights are your car’s way of telling you something is wrong — whether it’s a serious mechanical fault or an emissions issue. Here's why they matter in the MOT context:

? Engine Management Light (EML)

This can be triggered by a wide range of issues — from a misfire to a faulty sensor or even a loose fuel cap. Regardless, if the EML is on, it's a Major fault, and your vehicle will fail the MOT.

? ABS or Brake Warning

Anything related to the braking system is treated very seriously in an MOT. If the ABS or brake warning lights are on, they represent a critical safety risk.

? Airbag or SRS Light

A lit airbag warning light means your vehicle’s supplementary restraint system might not work in a crash — and that’s a safety system failure.

? TPMS Warning

For newer cars, a faulty or inactive tyre pressure monitoring system can be a failure if the system isn’t operating correctly.

? Understanding Warning Light Colours & Taking Action

⚪ What Do the Colours Mean?

• Green/Blue – Informational (e.g. lights on, full beam). Not testable.

• Amber/Orange – Advisory or performance issue. May be recorded but won't always fail you.

• Red – Serious fault. Often leads to failure.

? Can’t I Just Clear the Light?

Some drivers attempt to clear warning lights using basic scan tools. But MOT testers can often detect this, especially if fault codes remain in the system. Worse, clearing the light doesn’t fix the issue — it just hides the symptom.

? See how our professional diagnostics find and fix the root cause

? Brede Garage Uses SNAP-ON Solus Legend Diagnostics

We don’t just plug in a code reader — we use professional-grade SNAP-ON diagnostic tools that allow us to:

• Accurately diagnose warning lights

• Interpret fault codes with real-time data

• Carry out live tests and sensor readings

• Recommend fixes before your MOT deadline

? Book a pre-MOT check or diagnostic scan to save yourself time and stress.

? Preventing MOT Failures — What You Can Do

? Don’t Wait for Your MOT Reminder

If you notice a light on your dashboard, don’t assume it will go away. Booking a check a few weeks before your MOT gives you time to diagnose and fix the issue — rather than scrambling at the last minute.

? Use Warning Lights as an Early Warning System

Treat dashboard lights as an opportunity — not an inconvenience. Many faults are cheaper to fix early. Ignoring them can lead to more damage, higher bills, and a failed MOT.

? Explore how preventative servicing saves money in the long run

Book a Pre-MOT Check at Brede Garage ✅

At Brede Garage, we help you pass your MOT the first time with:

• SNAP-ON Solus Legend diagnostic checks

• Pre-MOT inspections

• Honest, straightforward advice

• Full servicing and repairs

? Book online today and give your car the all-clear before your test.