TPMS MOT Test: What You Need to Know

The Tyre Pressure Monitoring System, more commonly known as TPMS, is a crucial safety feature that has become increasingly prevalent in modern vehicles. For many motorists, a key question arises: when did this technology become a mandatory part of the MOT test? Understanding this transition is vital for ensuring your vehicle remains roadworthy and compliant with regulations.

The Introduction of TPMS into the MOT Test

The integration of TPMS into the MOT test was a significant step towards enhancing vehicle safety. For all cars that were first registered on or after the 1st of January 2012, the TPMS system is now subject to a check as part of their MOT inspection. This means that vehicles falling into this category, upon reaching their first MOT after this date, will have their TPMS functionality assessed. By 2015, a substantial number of these vehicles would have been undergoing their initial MOT tests, making TPMS a regular component of the examination.

Why TPMS is Important

The primary reason for TPMS inclusion in the MOT is safety. Underinflated tyres are a significant contributor to road accidents. They can lead to:

• Increased braking distances: When tyres lack the correct pressure, the contact patch with the road is compromised, leading to longer stopping times.
• Poor handling and stability: Incorrect tyre pressure can adversely affect how your vehicle steers and responds, especially during cornering or emergency manoeuvres.
• Increased risk of tyre blowouts: Over time, underinflated tyres can overheat due to increased flexing, making them more susceptible to sudden failure.
• Reduced fuel efficiency: Driving with underinflated tyres requires more energy, meaning your vehicle will consume more fuel.

TPMS alerts drivers to these potentially dangerous conditions, allowing them to rectify the issue before it escalates. The system typically alerts the driver via a warning light on the dashboard, indicating that one or more tyres are significantly underinflated.

Understanding Your TPMS System

It's important to understand that TPMS systems can vary. There are two main types:

Direct TPMS

These systems use sensors mounted inside each wheel that directly measure the air pressure and temperature in the tyre. These sensors transmit data wirelessly to the vehicle's central computer. Direct TPMS systems are generally more accurate but can be more expensive to maintain. If a sensor fails or its battery dies, it will need to be replaced.

Indirect TPMS

Indirect systems do not use actual pressure sensors in the wheels. Instead, they use the Anti-lock Braking System (ABS) wheel speed sensors to infer tyre pressure. If a tyre is underinflated, it will rotate faster than the others. The ABS system detects this difference and triggers the TPMS warning light. While simpler and often cheaper to maintain, indirect systems are less precise and may not detect a slow, gradual pressure loss as effectively as direct systems. They also require recalibration after inflating or rotating tyres.

Potential Costs and Maintenance

As mentioned, TPMS systems, particularly direct systems, can be expensive to maintain. The sensors have batteries that eventually deplete, usually after 5-10 years. Replacing these sensors, especially if they are integrated with the valve stem, can involve removing the tyre from the rim, leading to additional labour costs. Furthermore, the sensors themselves can be damaged by impacts or corrosion.

If your TPMS warning light illuminates, it's essential to address it promptly. Here's what you should do:

1. Check your tyre pressures manually: Use a reliable tyre pressure gauge to check the pressure in all tyres, including the spare if applicable. Inflate them to the manufacturer's recommended pressure, which can usually be found on a sticker in the driver's doorjamb or in the owner's manual.
2. Reset the TPMS: Some vehicles require a manual reset procedure after adjusting tyre pressures. Consult your owner's manual for instructions.
3. Visit a professional: If the warning light persists after checking and adjusting pressures, or if you suspect a fault with the TPMS sensors, it's best to visit a qualified mechanic or tyre specialist. They have the necessary diagnostic tools to identify the problem and replace any faulty components.

What Happens if Your TPMS Fails the MOT?

If your TPMS system is fitted to a vehicle registered after January 1st, 2012, and it is found to be faulty or the warning light is illuminated during the MOT test, your vehicle will fail. A defective TPMS system is considered a dangerous fault under the MOT testing rules. This means you will need to have the issue repaired before the vehicle can be retested and pass.

Frequently Asked Questions about TPMS and MOTs

Q1: My TPMS light is on, but my tyres look fine. Do I still need to worry?

A1: Yes. The TPMS light indicates a potential issue with tyre pressure or the system itself. Even if the tyres appear visually correct, they could still be significantly underinflated, posing a safety risk. It's crucial to check the actual pressure with a gauge and consult a professional if the light remains on.

Q2: My car was registered before January 1st, 2012. Is TPMS checked on my MOT?

A2: No. The mandatory TPMS check applies only to vehicles first registered on or after January 1st, 2012. However, if your vehicle is fitted with TPMS as standard or an aftermarket addition, and the warning light is illuminated, it could still be considered a defect, although it might not be the primary reason for failure if the system isn't mandated for your vehicle's age.

Q3: How much does it cost to replace a TPMS sensor?

A3: The cost can vary significantly depending on the make and model of your vehicle and the type of TPMS sensor. Expect to pay anywhere from £50 to £150 per sensor, plus labour costs for fitting and programming. It's advisable to get a quote from your local garage.

Q4: Can I ignore the TPMS warning light?

A4: It is strongly advised not to ignore the TPMS warning light. Doing so not only compromises your safety and the safety of others on the road but could also lead to a failed MOT test for vehicles that are required to have a functioning TPMS.

Q5: What is the recommended tyre pressure for my car?

A5: The recommended tyre pressure for your car can be found on a sticker located on the driver's side doorjamb, in the glove compartment, or in your vehicle's owner's manual. It's important to check and adjust pressures when the tyres are cold.

Conclusion

The integration of TPMS into the MOT test for vehicles registered from January 1st, 2012, onwards underscores the growing importance of tyre pressure in vehicle safety. Understanding how your TPMS works, its potential maintenance needs, and the implications for your MOT are essential for any responsible driver. Regularly checking your tyre pressures and addressing any TPMS warnings promptly will not only help you pass your MOT but, more importantly, will contribute to a safer driving experience.