MOT Test: What's Checked?

The annual MOT test is a legal requirement for vehicles in the UK that are over three years old. It's a comprehensive inspection designed to ensure your car is safe to drive and meets environmental standards. Many drivers, however, are unsure about the specifics of what's actually checked during an MOT. Understanding the process can help you prepare your vehicle and avoid common failure points. This article will delve into the various components and systems examined during an MOT test, giving you a clear picture of what to expect.

The Purpose of the MOT Test

The primary goal of the MOT test is to ensure vehicles on UK roads are safe, environmentally friendly, and comply with roadworthiness standards. It's not a substitute for regular servicing, but rather a safety and emissions check performed annually. Passing an MOT means your vehicle is deemed safe for use on public roads for the next 12 months. Failing an MOT means your vehicle has one or more defects that need to be rectified before it can be legally driven.

What Exactly is Checked?

An MOT test covers a wide range of checks across your vehicle. These can be broadly categorised into several key areas:

1. Vehicle Identification Number (VIN)

The VIN is a unique 17-character code that identifies your vehicle. The tester will check that the VIN is present, legible, and matches the details on the vehicle's registration certificate (V5C). A missing, damaged, or incorrect VIN can lead to a failure.

2. Body and Vehicle Structure

This is a crucial area, focusing on the overall integrity and safety of your car's bodywork. The tester will inspect for:

• Corrosion: Significant corrosion in specific areas, such as around suspension mounts, within the chassis, or affecting structural components, is a common reason for failure. The tester will tap panels to check for rust.
• Damage: Any sharp edges, protruding parts, or damage that could pose a risk to other road users or occupants will be assessed. This includes damage to the doors, bonnet, boot lid, and bumpers.
• Security: All doors must open and close correctly from both the inside and outside. The bonnet and boot must also be securely fastened.
• General Condition: The overall condition of the bodywork is checked for any obvious structural weaknesses.

3. Lighting Equipment

All lights on your vehicle must be functioning correctly and be the correct colour. This includes:

• Headlights (dipped and main beam)
• Tail lights
• Brake lights (including the high-level brake light)
• Indicator lights (front, rear, and side)
• Number plate lights
• Front and rear fog lights (if fitted)

The tester will check for correct operation, alignment, and any damage to the lenses.

4. Steering and Suspension

The steering and suspension systems are vital for vehicle control and safety. Checks include:

• Steering System: The tester will check for excessive play in the steering wheel, damage to steering components like the rack and track rod ends, and ensure the power steering is functioning correctly.
• Suspension: Components like shock absorbers, springs, and wishbones are inspected for wear, damage, or leaks. Excessive play or corrosion in suspension mounting points can lead to failure.
• Wheel Bearings: The tester will check wheel bearings for excessive play.

5. Tyres and Wheels

Tyres are a critical safety component. The MOT test examines:

• Tread Depth: Tyres must have a minimum tread depth of 1.6mm across the central three-quarters of the tyre's width.
• Condition: Tyres must be free from cuts, bulges, or other damage that could compromise their safety.
• Inflation: While not explicitly checked for pressure, obvious under or over-inflation that affects the tyre's profile might be noted.
• Wheel Condition: Wheels will be checked for damage or corrosion that could affect their integrity.
• Tyre Type: All tyres fitted must be of the appropriate type for the vehicle.

6. Brakes

The braking system is paramount for safety. The MOT test involves a rigorous inspection:

• Brake Performance: Using a roller brake tester, the tester will measure the braking efficiency of each wheel and the overall braking force.
• Brake System Components: The tester will visually inspect brake pipes, hoses, callipers, discs, and drums for leaks, corrosion, or damage.
• Handbrake: The effectiveness and condition of the parking brake (handbrake) are also assessed.

Brake performance is a key factor in passing the MOT.

7. Exhaust Emissions

Your vehicle's exhaust emissions are tested to ensure they meet current environmental standards. The specific tests vary depending on the age and fuel type of your vehicle:

• Petrol Vehicles (post-1996): Tested using a gas analyser to measure carbon monoxide (CO), hydrocarbons (HC), and lambda values.
• Diesel Vehicles (post-2008): Tested for smoke opacity using a smoke meter.
• Catalytic Converters: Vehicles fitted with catalytic converters must have them in place and functioning correctly.

Emissions are a significant factor for older vehicles.

8. Fuel System

The fuel system is checked for leaks and the condition of fuel pipes and hoses. The fuel cap must also be present and secure.

9. Seats and Seatbelts

All seats and seatbelts must be in good condition and functioning correctly:

• Seats: Must be securely fixed to the vehicle.
• Seatbelts: All seatbelts must be present, correctly fitted, and function properly. The tester will check for wear, damage, and the effectiveness of the locking mechanism.
• Child Restraints: While child seats themselves aren't tested, the anchor points for them are checked.

10. Windscreen, Wipers, and Washers

Visibility is key to safe driving:

• Windscreen: The MOT test checks for damage or chips in the windscreen that could obstruct the driver's view. A chip larger than 10mm in the driver's line of sight, or larger than 40mm elsewhere, will result in a failure.
• Wipers: Must be in good working order and effectively clear the windscreen.
• Washers: Must be able to spray water onto the windscreen.

11. Horn

The horn must be present and in working order. It should sound clearly when operated.

12. Mirrors

All mirrors (door mirrors and interior mirror) must be present, securely fitted, and in good condition.

13. Doors, Handles, and Hinges

As mentioned earlier, doors must open and close properly from both inside and outside. Handles and hinges must be secure and not damaged.

14. Number Plate

The number plate must be present, securely attached, and legible. The characters must be the correct size and spacing.

15. Other Equipment

Various other components are also checked, including:

• Speedometer: Must be present and functioning.
• Engine: While the engine's internal mechanics aren't tested, the engine must not be leaking excessive oil, and the engine management system warning lights (like the 'check engine' light) must not be illuminated.
• Exhaust System: Checked for leaks, security, and excessive noise.
• Battery: Must be securely fastened.
• Sump: Must not be leaking oil.

What Happens if Your Car Fails the MOT?

If your car fails its MOT, you will receive a refusal certificate detailing the reasons for failure. You have a few options:

• Repair and Re-test: You can have the necessary repairs carried out and then have your vehicle re-tested. If you leave the vehicle at the test centre for repair, the re-test is usually free if completed within 10 working days.
• Drive Away: If your MOT has expired, you generally cannot drive your car away. However, there are exceptions if you are driving to a pre-booked MOT appointment or to a place of repair.

Common MOT Failure Points

Understanding common reasons for failure can help you prepare your car:

Preparing Your Vehicle for the MOT

While the MOT is a comprehensive check, some basic pre-checks can help prevent a failure:

• Check all lights: Ensure all bulbs are working and lenses are clean and undamaged.
• Tyre condition: Inspect tyres for tread depth and any visible damage.
• Windscreen: Clean it thoroughly and check for any chips or cracks.
• Fluid levels: Ensure your screenwash is topped up.
• General cleanliness: A tidy interior can make the tester's job easier, though it doesn't directly affect the pass/fail.

Frequently Asked Questions

What is the minimum tyre tread depth for an MOT?

The legal minimum tread depth for car tyres in the UK is 1.6mm across the central three-quarters of the tyre's breadth.

Can I drive my car if it fails its MOT?

You can only drive your car if its MOT has not expired and you are driving it to a pre-booked MOT appointment or to a place of repair. Otherwise, driving an unroadworthy vehicle is illegal and dangerous.

Does the MOT test the engine's performance?

No, the MOT does not test the engine's performance or the general mechanical condition of the engine. It focuses on safety-critical items and emissions. Regular servicing is required for engine health.

What happens if my 'check engine' light is on?

If your 'check engine' warning light is illuminated on the dashboard, your vehicle will fail its MOT test.

How long does an MOT test take?

An MOT test typically takes between 45 minutes and an hour to complete, depending on the type of vehicle and the test centre.

The MOT test is a vital part of ensuring your vehicle is safe and legal to drive. By understanding what is checked, you can be better prepared and help ensure your car passes its annual inspection with flying colours. Regular maintenance, beyond the MOT requirements, is always recommended for optimal vehicle safety and longevity.

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