These 7 Common MOT Fails Could Cost You Hundreds: Getting an MOT (Ministry of Transport) test for your vehicle can be stressful, especially when you consider the potential costs of failing. These 7 common MOT fails could cost you hundreds if left unchecked. The good news? Most of them are easy to fix once you know what to look for—and addressing them early can save you more than just money.
In this comprehensive, professional guide, we’ll walk you through the most frequent MOT failures, explain how to spot problems early, and show you how to resolve them quickly and affordably. Whether you’re a new driver learning the ropes, a seasoned car enthusiast who wants to fine-tune their knowledge, or an automotive professional advising clients, these insights are tailored to help you pass your MOT with flying colours.
These 7 Common MOT Fails Could Cost You Hundreds
| Issue | Why It Fails MOT | How to Fix It | Quick Stats |
|---|---|---|---|
| Lights & Signalling | Broken, blown, or misaligned lights | Regularly inspect and replace faulty bulbs | 18.9% of all MOT failures (DVSA) |
| Suspension | Worn shock absorbers or springs | Perform bounce test and replace faulty parts | 13% of failures (DVSA) |
| Brakes | Worn pads or discs, faulty handbrake | Listen for noises; test braking response | 10% failure rate (DVSA) |
| Tyres | Low tread depth, damage | Use the 20p test and inflate to correct pressure | 7.7% of failures (DVSA) |
| Windscreen & Wipers | Chips, cracks, worn blades | Replace blades; repair damage, fill washer fluid | Common cause of visibility issues |
| Number Plates | Illegible, dirty, or poorly attached plates | Clean, secure, and replace damaged plates | Simple but often overlooked issue |
| Exhaust & Emissions | Excessive emissions, leaks | Warm up engine before test; fix leaks | Especially common for older diesel vehicles |
Failing your MOT can feel like a financial setback, but it doesn’t have to be. By knowing what to look for and performing regular vehicle checks, you can easily avoid most failures. These 7 common MOT fails—from lights and brakes to tyres and emissions—are all preventable with proactive care.
Staying on top of these checks helps ensure your vehicle remains safe, roadworthy, and compliant with UK law. Whether you’re a daily commuter or managing an entire fleet, taking action now means fewer surprises later.
Why Understanding MOT Fails Matters
Every vehicle over three years old in the UK must undergo an annual MOT test to ensure it meets road safety and environmental standards. Driving without a valid MOT is not only illegal but could also invalidate your insurance, resulting in serious penalties.
Failing an MOT can feel overwhelming, especially when it reveals issues that weren’t obvious to the average driver. However, most failures are due to minor faults that can be fixed quickly. Identifying and addressing these problems ahead of time will ensure your car remains safe, roadworthy, and legal to drive.
Here’s a closer look at each of the most common MOT failure categories, along with practical advice to prevent or resolve them.
1. Lights and Signalling
Issue: Blown bulbs, faulty indicators, misaligned or obscured headlights.
Why it fails: Functional lighting is essential for driver visibility and communication with other road users. If any of your lights are not working or are incorrectly aligned, it could compromise safety.
How to fix it fast:
- Perform a complete light check weekly: headlights, indicators, reverse lights, fog lamps, and number plate lights.
- Replace any faulty or flickering bulbs. Most are inexpensive and easy to change.
- Clean foggy or dirty light covers with a soft cloth and appropriate cleaner.
Pro Tip: Keep spare bulbs in your glove box for emergencies, especially during winter months when daylight is limited.
2. Suspension Problems
Issue: Worn-out springs, leaking shock absorbers, loose suspension arms.
Why it fails: The suspension system affects both ride comfort and vehicle control. A damaged suspension compromises handling, increases tyre wear, and can reduce braking effectiveness.
How to fix it fast:
- Do a bounce test: push down firmly on each corner of your car. If it bounces more than twice, your shock absorbers may be worn.
- Drive over speed bumps slowly and listen for unusual knocking sounds.
- Have a mechanic inspect the suspension during regular servicing.
Additional Insight: Uneven tyre wear and an unbalanced ride are often signs of hidden suspension issues. Fixing them early reduces wear on other parts and improves fuel economy.
3. Brakes
Issue: Worn brake pads or discs, ineffective handbrake, uneven braking.
Why it fails: Faulty brakes are a major safety concern. If your vehicle cannot stop properly or evenly, you pose a risk to yourself and others on the road.
How to fix it fast:
- Be alert to high-pitched squeals or grinding noises.
- Monitor brake performance: if your pedal feels soft or the car pulls to one side, get it checked.
- Inspect the handbrake by pulling it on a slope to ensure the vehicle remains stationary.
Maintenance Tip: Change brake pads before they wear down to the metal, which can damage discs and significantly raise repair costs.
4. Tyres
Issue: Inadequate tread depth, sidewall damage, under- or over-inflation.
Why it fails: Tyres play a vital role in grip and handling. Worn or poorly inflated tyres can increase stopping distances and affect cornering, especially on wet roads.
How to fix it fast:
- Perform the 20p test regularly. UK law requires a minimum tread depth of 1.6mm across the central three-quarters of the tyre.
- Check tyre pressure monthly using a reliable gauge. The correct pressure is listed in your vehicle’s manual or on the door frame sticker.
- Look for bulges, cracks, or embedded objects and replace tyres as needed.
Did You Know?: A mismatched set of tyres or having different tread depths can also cause MOT failure if handling is affected.
5. Windscreen, Wipers, and Washers
Issue: Obstructed driver vision due to windscreen damage, worn wipers, or empty washer reservoir.
Why it fails: Good visibility is crucial. Even a small chip in the driver’s line of sight can be enough to fail an MOT.
How to fix it fast:
- Inspect the windscreen for chips and cracks. Many garages offer free repairs through your insurance.
- Replace windscreen wipers annually or when they smear or miss water.
- Top up washer fluid regularly and ensure nozzles are unclogged.
Visibility Tip: Keep a bottle of screen wash in your boot and use a de-icer in winter to reduce wear on your wiper blades.
6. Number Plates
Issue: Plates that are obscured, faded, damaged, or loosely attached.
Why it fails: Number plates must be clearly legible at all times. If they are unreadable, police cameras and ANPR (Automatic Number Plate Recognition) systems won’t work properly.
How to fix it fast:
- Clean your plates with a mild detergent.
- Replace damaged or incorrectly spaced plates with new ones from a DVLA-registered supplier.
- Check for secure mounting—loose plates can fall off or obscure numbers.
Legal Note: Custom fonts, incorrect spacing, or tinted covers are not allowed and will lead to automatic failure.
7. Exhaust and Emissions
Issue: Leaky exhausts, noisy pipes, or failing emissions standards—especially for diesel engines.
Why it fails: Vehicles must meet environmental standards for noise and emissions. A noisy or leaky exhaust can result in failing the test and polluting the air.
How to fix it fast:
- Listen for loud or unusual noises from the exhaust system.
- Check for visible smoke—blue or black smoke often indicates engine or fuel issues.
- Use a fuel system cleaner or engine treatment before your test.
Diesel Alert: If your diesel car has a DPF (Diesel Particulate Filter), ensure it’s not blocked. Take the car on a longer drive beforehand to allow regeneration.
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FAQs About These 7 Common MOT Fails Could Cost You Hundreds
Q1: Can I drive my car if it fails the MOT?
No. You can only drive it to a pre-booked MOT or repair appointment. Otherwise, it’s illegal and may void your insurance.
Q2: How long does an MOT test take?
Most MOT tests take between 45 minutes and an hour. If your car fails, repair time will vary.
Q3: How much does an MOT cost?
As of now, the maximum charge for an MOT test is £54.85. Prices may be lower at some garages.
Q4: When should I book my MOT?
You can book your MOT up to one month (minus one day) before the expiry date without losing your renewal date.
Q5: Are advisory notes important?
Absolutely. Advisory notes flag items that may soon fail or need attention. Addressing them promptly can prevent major repairs.
