A routine check of your car’s DPF filter might not feel like a top priority, and many drivers overlook the subtle signs of a blockage. However, keeping the filter clean is essential, not only for maintaining your vehicle’s performance but also for passing your MOT. With the 2025 MOT updates bringing in stricter emissions checks, a clean DPF has never been more important.
For this reason, it’s important to pay attention to DPF signs on your dashboard and arrange professional DPF cleaning for your car as soon as possible. DPF filters are your vehicle’s first line of defence against harmful emissions, trapping soot and particulate matter from your diesel engine. A clogged DPF can restrict your car’s exhaust gas flow, build pressure, lead to sluggish acceleration, a visible power loss, and a decrease in your engine’s performance.
A blocked DPF is also responsible for reduced fuel efficiency, (sometimes up to 10-15 %), and can even cause engine damage in extreme cases.
Let’s break down all you need to know about DPF cleaning.
1. What MOT Testers Look for in DPF Checks
MOT testers carry out visual inspections of the DPF. This may involve checking the exhaust system under the vehicle and whether the DPF is intact. A tampered or gutted DPF may be marked as a defect even if your emissions are in check. This is because visual checks are now mandatory to meet regulatory requirements.
DPF signs on your dashboard, like the exhaust symbol or “check engine” light, can lead to MOT failure, as this indicates a malfunction with your emission systems. Previously, some of these dashboard warning signs were not taken seriously, but under the new MOT test changes as of April 2025, these rules have changed.
MOT testers also conduct enhanced sensor-based emission checks as part of MOT inspections, and any signs of visible smoke during this test are considered to be a major fault.
So if you’re wondering what to do when the DPF light comes on, consider getting your DPF filter cleaned. It’s best to leave this in the hands of experienced mechanics at garages like In Town, who use specially formulated treatments to perform DPF cleaning. To learn more, get in touch.
2. How to Prevent MOT Failure from a Dirty DPF
DPF cleaning is an essential part of regular car maintenance. Since it’s also an important part of passing your MOT, it’s best not to ignore the DPF signs on your dashboard. The best way to keep your car and emissions systems in good condition is by cleaning the DPF filter.
However, you could also use a method called ‘DPF regeneration’, which is your filter’s way of self-cleaning. You can do this by taking your car for a short, fast drive to make your car’s exhaust reach a high temperature. This triggers DPF regeneration. How do you know this method is working? Your vehicle may show signs like an odour, changes in your engine’s noise or an increase in idle speeds.
It’s important to complete this regeneration cycle by driving continually for at least 30 minutes. Ensure that you do not turn off the engine during this process. You could also use DPF cleaner additives that can help make this regeneration process more effective.
3. Why Professional DPF Cleaning Matters
DPF filters are bound to become clogged over time, even with regular maintenance and cleaning. This is particularly true with ash build-up in filters, where standard methods like regeneration are often ineffective. In these cases, professional DPF cleaning services, such as those offered by award-winning garages like In Town, provide a reliable solution.
This is because even though fuel additives are helpful, they prove inadequate in DIY methods to clean your filter. Professional DPF cleaning is beneficial for your car because it uses specialised treatments and equipment to deal with stubborn soot deposits and ash. Professional DPF cleaning can restore your DPF filter to near factory condition, minimising the need for costly filter replacements.
Your vehicle’s emission system benefits from a professional DPF clean. Instead of wondering what to do when a DPF light comes on, you’ll be able to enjoy a smoother performance and greater peace of mind on the road.
For a Professional DPF Cleaning Service, Contact In Town Today
Now that you know all about blocked DPF filters and how important it is to keep them clean, why not get a professional DPF cleaning done at our award-winning garage? In Town Automotive is renowned for its top-class services to keep your vehicle MOT-ready and in optimal condition.
We offer specialised DPF cleaning treatments for your vehicle, like the all-in-one carbon cleaning and Forte DPF cleaning. Keeping your emissions systems in good condition through regular servicing and filter cleaning can help you avoid costly repairs and filter replacements.
We also use top-of-the-line vehicle diagnostics to conduct full-service scans, and are considered the best MOT centre in Northampton.
To keep your car running safely and efficiently, we recommend sending it in for an all-inclusive health check. We have years of experience in fixing air conditioning, cambelts, exhausts, wheel alignment, and much more.
Consider visiting our services page or contacting us to book an appointment today.
bookings@intownautomotive.co.uk