MOT Test: What's Checked?

Understanding Your Vehicle's MOT Test: A Comprehensive Guide

The MOT (Ministry of Transport) test is an annual assessment that every vehicle over three years old in the UK must pass to prove it is safe and roadworthy. It's a crucial part of vehicle maintenance, designed to ensure that vehicles on our roads meet minimum safety and environmental standards. Many motorists, however, aren't entirely sure what actually gets checked during an MOT. This comprehensive guide will break down the key areas and components that examiners scrutinise, giving you a clearer understanding of what to expect and how to prepare your vehicle.

The MOT test is not a check of the mechanical condition or general wear and tear of your vehicle. It does not cover the engine, gearbox, clutch, or other major mechanical components. Instead, it focuses on the parts of your car that are essential for safety and environmental compliance. Passing an MOT means your vehicle meets the minimum requirements to be driven legally on public roads.

Key Areas Inspected During an MOT Test

The MOT test is divided into several categories, each focusing on specific aspects of your vehicle's safety and environmental performance. Let's delve into each of these:

1. Body and Structure

This section of the MOT checks for excessive corrosion or damage to the vehicle's bodywork that could affect its structural integrity. Key areas include:

• Chassis and Frame: Inspectors will look for any signs of serious corrosion, distortion, or cracks that could compromise the vehicle's strength.
• Wheel Bearings: While not directly part of the body, wheel bearings are checked for excessive play or noise, which can indicate wear and potential failure.
• Doors: Doors must open and close correctly from both the inside and outside. Latches and hinges are checked for secure operation.
• Bonnet and Boot: These must be securely fastened and openable from the outside.
• Bumpers: Bumpers must be securely attached and not excessively damaged or protruding.
• General Condition: The overall condition of the bodywork is assessed for any sharp edges or protrusions that could be a hazard.

2. Fuel System

The fuel system is checked for leaks and secure connections. This is vital for preventing fuel spills and potential fire hazards.

• Fuel Tank: The fuel tank must be secure and free from leaks.
• Fuel Lines: Fuel lines should be properly connected, free from leaks, and not corroded.

3. Exhaust Emissions

This is a critical part of the MOT, focusing on your vehicle's environmental impact. The test measures the level of pollutants emitted from your exhaust system.

• Exhaust Gas Analysis: A gas analyser is used to measure CO (carbon monoxide), HC (hydrocarbons), O2 (oxygen), and NOx (nitrogen oxides) levels. The acceptable limits vary depending on the age and type of vehicle.
• Diesel Particulate Filter (DPF): For diesel vehicles, the presence and effectiveness of the DPF are checked. A missing or tampered DPF can lead to an MOT failure.
• Visible Smoke: Any excessive smoke from the exhaust is also a reason for failure.

4. Lighting Equipment

All exterior lights are checked for proper function, aim, and condition. This is essential for visibility and signalling to other road users.

• Headlights: Both dipped and main beam must function correctly and be correctly aimed. The lenses should not be excessively damaged or discoloured.
• Tail Lights: Rear lights must illuminate correctly.
• Brake Lights: All brake lights must illuminate when the brake pedal is pressed.
• Indicator Lights: Front, rear, and side indicators must flash at the correct rate and be visible.
• Hazard Lights: The hazard warning lights must function correctly.
• Number Plate Lights: The rear number plate must be illuminated.
• Reflectors: Rear reflectors must be present and in good condition.

5. Steering and Suspension

This category ensures your vehicle handles and steers correctly, contributing significantly to road safety.

• Steering Wheel: The steering wheel should be secure and not excessively worn.
• Steering Rack and Box: Checked for excessive play or damage.
• Power Steering: If fitted, the power steering system must be functioning correctly and not leaking.
• Suspension Components: Shock absorbers, springs, arms, and links are inspected for wear, damage, or leaks.
• Wheel Bearings: As mentioned earlier, checked for play.

6. Brakes

The braking system is one of the most critical safety components and is subjected to rigorous checks.

• Brake Pedal: The pedal should feel firm and not sink to the floor.
• Brake Fluid: The level should be within the recommended range, and the reservoir should not be leaking.
• Brake Lines and Hoses: Checked for leaks, corrosion, or damage.
• Brake Discs and Pads: Inspected for wear, damage, or warping.
• Brake Calipers: Checked for leaks or damage.
• Parking Brake (Handbrake): Must hold the vehicle securely on a roller brake tester.
• ABS Warning Light: The ABS warning light should illuminate on ignition and then go out.
• Electronic Stability Control (ESC): If fitted, the ESC warning light is also checked.

A brake performance test is carried out using a roller brake tester to measure the efficiency of both the service brake and the parking brake.

7. Tyres and Wheels

The condition and security of your tyres and wheels are paramount for grip and control.

• Tyre Tread Depth: The legal minimum tread depth is 1.6mm across the central three-quarters of the tyre's width.
• Tyre Condition: Tyres must not have any cuts, bulges, or significant damage.
• Tyre Pressure: While not directly tested, ensuring correct tyre pressures is good practice.
• Wheel Nuts and Bolts: Must be present and secure.
• Wheels: Checked for damage or distortion.

8. Windscreen and Wipers

Visibility is key, so the windscreen and wipers are thoroughly checked.

• Windscreen: The windscreen must be free from chips or cracks in a specific area that could obstruct the driver's view (the area swept by the wipers on the driver's side).
• Wipers: Wipers must be in good condition and effectively clear the windscreen.
• Washers: The washer system must spray water onto the windscreen.

9. Horn

The horn must be functional and audible.

• Horn Operation: The horn must sound when operated.

10. Seats and Seatbelts

Ensuring occupants are safely secured is vital.

• Seat Framework: Seat frames must not be excessively corroded.
• Seat Backs: Seat backs must be secure.
• Seatbelts: All fitted seatbelts must be present, correctly functioning, and free from damage. The locking mechanism and anchorages are also checked.

11. Speedometer

The speedometer must be working correctly.

• Speedometer Function: The speedometer must be visible and functioning.

12. Other Equipment

Several other items are checked, including:

• Mirrors: All mirrors must be present, secure, and in good condition.
• Doors: As mentioned earlier, must open and close from both inside and outside.
• Vehicle Identification Number (VIN): Must be present and legible.
• Registration Plate: Must be correctly displayed and legible.

What is NOT Checked in an MOT?

It's important to remember that the MOT test is a snapshot of your vehicle's condition on a specific day. It does not cover:

• Engine: The internal workings of the engine, including oil levels, leaks, or performance.
• Gearbox: The condition or performance of the gearbox.
• Clutch: The operation or wear of the clutch.
• Battery: The condition or charge of the battery.
• Tyre Pressures: While important for safety, they are not officially tested.
• Air Conditioning: The operation of the air conditioning system.
• Bodywork Condition (Minor): Minor cosmetic damage or superficial rust that doesn't affect structural integrity.

MOT Test Categories and Failure Reasons

During an MOT test, components are classified into three categories:

• Dangerous: A defect that poses a direct and immediate risk to road safety or has a serious impact on the environment. A vehicle with a dangerous defect will fail its MOT.
• Major: A defect that is likely to reduce the safety of the vehicle or have an impact on the environment. A vehicle with a major defect will fail its MOT.
• Minor: Defects that have no obvious detrimental effect on the safety of the vehicle or impact on the environment. A vehicle with only minor defects may still pass its MOT, but the defects should be repaired as soon as possible.

If your vehicle fails the MOT, you will be given a 'refusal of an MOT certificate' which details the reasons for failure. You can then have the necessary repairs carried out, and your vehicle can be re-tested. If the re-test is carried out within 10 working days at the same test centre, certain items may only be re-inspected, rather than a full MOT test being required.

Preparing Your Vehicle for its MOT

To give your vehicle the best chance of passing its MOT, consider the following:

• Check Lights: Ensure all bulbs are working and the lenses are clean and undamaged.
• Tyre Tread: Make sure your tyres have at least 1.6mm of tread and are free from damage.
• Windscreen: Clean your windscreen and check for any chips or cracks.
• Mirrors: Ensure all mirrors are securely fitted and not cracked.
• Horn: Test that the horn works.
• Wipers and Washers: Check that the wipers clear the screen effectively and the washers spray water.
• Brake Fluid: Check the brake fluid level.
• General Condition: Remove any excessive rubbish from the car, especially the boot and footwells.

Frequently Asked Questions (FAQs)

Q1: How often do I need an MOT?
A1: For vehicles registered before 1st January 1962, an MOT is not required. For vehicles aged between 3 and 40 years old, an MOT is required annually. For vehicles over 40 years old, an MOT is generally not required unless they have undergone substantial changes.

Q2: Can I drive my car if it fails its MOT?
A2: You can drive your car if it has a valid MOT certificate and you are taking it to be repaired or to a pre-booked MOT test. However, you cannot drive it if its current MOT has expired and it has failed the new test, as it is deemed not roadworthy.

Q3: What happens if my car fails the MOT?
A3: If your car fails, you will receive a refusal certificate. You must get the identified faults repaired. You can then have a partial or full re-test depending on when and where the re-test is conducted.

Q4: Does the MOT test check the engine?
A4: No, the MOT test does not check the mechanical condition of the engine, gearbox, clutch, or other internal components. It focuses on safety and emissions.

Q5: What is the minimum tyre tread depth for an MOT?
A5: The legal minimum tyre tread depth for an MOT is 1.6mm across the central three-quarters of the tyre's breadth.

Understanding the MOT test process and what is checked can help you prepare your vehicle and avoid unexpected failures. Regular maintenance, beyond just the MOT, is crucial for ensuring your vehicle remains safe and reliable on the road.

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