Your TPMS light is on. That amber tyre-shaped warning on your dashboard is your Tyre Pressure Monitoring System. It alerts you that one or more tyres are 25% or more below the manufacturer’s recommended pressure, or that the system has detected a fault.
Do not ignore it. In the UK, tyre-related defects contributed to 159 killed or seriously injured casualties on our roads. Underinflation is one of the most common and preventable causes.
If your TPMS light stays on even after correcting the tyre pressure, it may indicate a faulty valve or sensor, which might need TPMS valve replacement.
Not sure what’s actually causing the warning? We’ll break down exactly what your TPMS light means, the difference between warning types, and the step-by-step actions you should take to fix it safely.
What Does the TPMS Light Mean?
The TPMS light means your Tyre Pressure Monitoring System has detected a problem, either a tyre is significantly underinflated, a sensor has failed, or the system itself has a malfunction. It illuminates when tyre pressure drops approximately 6–7 PSI below the recommended level.
There are 2 types of TPMS used in UK vehicles:
- Direct TPMS: Uses a physical pressure sensor inside each wheel valve. It sends real-time pressure and temperature data to the car’s ECU. More accurate, no recalibration needed after inflation.
- Indirect TPMS: Uses ABS wheel-speed sensors to detect pressure loss via changes in rotation speed. Requires manual recalibration when tyres are rotated or pressures adjusted.
TPMS is a legal requirement for all M1 passenger vehicles first used on or after 1 January 2012, under UK law retained from EU Directive 2010/48/EU. From 1 January 2015, a faulty TPMS results in a Major MOT defect, an automatic MOT failure.
TPMS Warning Light: Solid vs Flashing – What’s the Difference?
The way the TPMS warning light behaves tells you exactly what kind of problem you have.
Solid Amber Light
A solid, continuously lit TPMS light means one or more tyres are below the safe pressure threshold. This is the most common cause. It does not necessarily mean a system fault; it often means a slow puncture or natural pressure loss over time.
Check all four tyre pressures immediately using a pressure gauge. Inflate to the correct PSI (found on the driver’s door jamb or owner’s manual). If the pressure is correct and the light stays on, suspect a sensor fault.
Flashing Then Solid Light
A TPMS light that flashes for 60–90 seconds before staying on indicates a system malfunction, not just low pressure. This could mean a sensor battery has died, the sensor has been damaged, or there’s an ECU communication fault.
According to the GOV.UK MOT Inspection Manual, a warning lamp that ‘flashes several times and then remains on’ may indicate a system malfunction requiring assessment.
This is a Major MOT defect. Book a diagnostic scan as soon as possible.
Light Comes On in Cold Weather
Tyre pressure decreases by approximately 1 PSI for every 10°F (5.5°C) drop in temperature. In a UK winter, this means your TPMS light can illuminate on cold mornings and turn off once the tyres warm up.
Check and inflate all tyres to the correct cold PSI when the car has been stationary for at least 4 hours. The light should extinguish.
What to Do If Your TPMS Light Comes On
Take these 5 steps in order:
Step 1: Stay calm and do not brake suddenly. Reduce speed gradually and pull over safely if the light illuminates while driving.
Step 2: Visually inspect all four tyres. Look for obvious signs of a flat, sidewall damage, or a nail/screw in the tread. It is better to check the tyre tread.
Step 3: Check tyre pressure with a gauge. Use an air pump at a petrol station or a portable compressor. Compare readings against the recommended PSI for your vehicle.
Step 4: Inflate or change the tyre. If the pressure is simply low, inflate to the correct PSI. If it’s a puncture, use your spare tyre or call a mobile tyre fitting service.
Step 5: Reset the TPMS if needed. Some vehicles reset automatically after driving 10 minutes above 30 mph. Others require a manual reset or diagnostic reprogramming, especially after new tyres are fitted.
If the TPMS light is on due to a safety-critical tyre problem, the vehicle is unroadworthy and illegal to drive on UK roads. Choose the right mobile tyre fitter and get immediate help.
6 Common Causes of a TPMS Light
Use this table to identify your specific TPMS warning and the correct action to take:
Cause | Symptom | Urgency | Fix |
Low tyre pressure (puncture / natural loss) | Solid amber TPMS light | Stop safely within 1–2 miles | Inflate to the correct PSI or replace the tyre |
TPMS sensor battery dead (3–7 yr lifespan) | Solid or flashing light, no pressure reading | Not urgent, fix before MOT | Replace sensor (£45–£150 per unit in London) |
Sensor corrosion/damage (valve stem) | Intermittent or persistent light | Fix before the next tyre change | Service kit (£10–£30) or full sensor swap |
Temperature drop (cold weather) | Light on in the morning, clears when warm | Monitor, re-check pressure | Inflate tyres to correct cold PSI |
Post-tyre-change, sensor not re-paired | The light stays on after new tyres | Fix before driving far | Reprogram with a diagnostic tool |
System malfunction (ECU / wiring fault) | Flashing then solid light | Fix before MOT (Major defect) | Garage diagnostic scan required |
Sensor battery lifespan: 3–7 years or up to 150,000 miles.
How to Fix a TPMS Warning Light: 4 Solutions
A TPMS warning light doesn’t always mean something serious, but it should never be ignored. Most issues are quick to fix if you know where to look.
1. Inflate the Tyre to the Correct Pressure
This is the most common fix. Find the recommended PSI on the sticker inside your driver’s door jamb or in the owner’s manual, not on the tyre sidewall (that shows the maximum pressure, not the recommended operating pressure).
Always check the pressure when the tyre is cold (car stationary for 4+ hours) to get an accurate reading.
2. Repair or Replace the Tyre
If a puncture is the cause of pressure loss, a mobile tyre fitting technician can repair or replace the tyre at your location. A repair (plug or patch) typically costs £20–£30 in London. Replacement costs vary by tyre brand and size.
3. Replace or Service the TPMS Sensor
A TPMS service kit (valve cap, core, rubber grommet) should be replaced every time a tyre is removed or changed. The NTDA confirms that a service is significantly cheaper than full replacement, often one-third of the dealer price.
After fitting a new sensor, a specialist diagnostic tool is required to reprogram and pair it to your vehicle’s ECU. Make sure your fitter has this equipment before booking.
Never replace a TPMS sensor valve with a standard rubber valve. This will cause an MOT failure and remove a critical safety system.
4. Recalibrate Indirect TPMS After Tyre Changes
If your car uses indirect TPMS, the system must be recalibrated every time tyres are inflated, rotated, or replaced. Failing to do so will cause the TPMS light to remain on despite correct pressures.
Consult your owner’s manual for the specific reset procedure. On most vehicles, press the TPMS reset button (often located under the steering wheel or in the infotainment menu) with all tyres at the correct pressure, then drive at 50 mph for 10–15 minutes.
Expert TPMS Valve Replacement at Your Location
If your TPMS light remains on after inflating your tyres, there’s a strong chance the issue is a faulty valve or sensor that requires professional attention. Ignoring it can lead to ongoing warnings, slow air leaks, or even MOT failure.
Whether your warning light won’t reset or you suspect a leaking or damaged valve, My Mobile Tyres offers reliable TPMS valve replacement at your home, workplace, or roadside across London, saving you time and hassle.
All work is carried out using the correct tools and compatible components to ensure your TPMS system functions properly and your warning light is resolved correctly.
Ready to get your tyres sorted
We come to you anywhere in London, anytime of the day or night.
Frequently Asked Questions
Find quick answers to the most common questions our customers ask.
You can drive short distances if the tyre is still properly inflated and the light is caused by a sensor fault. However, if the tyre is visibly flat or severely underinflated, do not drive; this is illegal and dangerous. Have the tyre checked immediately.
TPMS sensor batteries last 3–7 years or approximately 150,000 miles. Cold UK winters can shorten battery life. Sensors cannot be battery-replaced in isolation; the entire sensor unit must be replaced when the battery fails.
For vehicles with indirect TPMS, the light may reset after driving at 50 mph for 10–15 minutes with correct tyre pressures. For direct TPMS with a sensor fault, the light will not reset until the faulty sensor is repaired or replaced and reprogrammed by a technician.
Yes. If your winter tyres are fitted on separate rims with their own TPMS sensors, those sensors must be registered to your vehicle. If you use the same rims as your summer tyres, the existing sensors remain, and no reprogramming is required.
After inflating all tyres to the correct cold PSI: (1) Locate the TPMS reset button, usually under the steering column or in the vehicle settings menu. (2) Press and hold for 3 seconds until the warning light blinks 3 times. (3) Drive at 30 mph or above for at least 20 minutes.