When the DPF warning light in your car comes on, this means that there’s a problem with the diesel particulate filter.
Usually, the light will come on if the DPF is becoming blocked or struggling to regenerate.
The light should go out once the regen process is complete, as long as you give the DPF enough time to reach a high enough temperature.
If it doesn't or the light keeps coming on, a professional mechanic will need to force DPF regeneration and clean or replace the DPF if needed.
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Should I Be Worried About This Light?
Your car’s diesel particulate filter has an important role to play in reducing harmful emissions and maintaining engine performance.
Ignoring your DPF warning light can cause your diesel vehicle to enter ‘limp home' mode, which can severely limit your performance and lead to more serious problems.
Once this exhaust warning light comes on, this is a sign that your DPF filter is nearly fully blocked.
The DPF warning light looks like a piped box with dots in the middle, but this can vary by manufacturer.
The light can be either flashing or solid, depending on how blocked the filter is.
Flashing DPF Light
If your DPF light flashes, this means that the level of soot is almost at full capacity.
When your DPF is 70% full of soot, your car will enter ‘limp home’ mode and vehicle performance will be restricted.
Solid DPF Light
A yellow or amber DPF light can tell you that you’re approaching maximum soot levels.
This means your car needs to go through the regeneration process to unblock your DPF.
By the time your DPF is 90% full of soot, there will be little you can do to prevent the need for a full-on DPF replacement.
What Causes the DPF Light to Come On?
The DPF warning light will come on if your filter is becoming clogged or struggling to properly regenerate.
There are two types of DPF regeneration: active and passive.
Whilst active regen is triggered automatically by your car’s ECU once you’ve reached a certain temperature, passive regen can be triggered when you drive at around 40mph on the motorway for 20 minutes or more.
The light should go out once the regen process is complete – but you must give the DPF time to reach its higher temperature for this to work.
If you frequently take your car for shorter drives at lower speeds, this can cause the DPF to become blocked, as it won’t have time to fully regenerate.
Faulty sensors or low-quality fuel could also be to blame.
How Do You Clear a DPF Warning Light?
If your DPF warning light has come on, the process of clearing it will vary depend on what’s causing it to stay on.
You can try to clear this exhaust warning light by driving on the motorway for 15 minutes or more at a speed of at least 40mph.
Otherwise, you can visit a garage so that they can diagnose the underlying cause of the blockage.
A DPF clean or replacement may be necessary, depending on how blocked the filter has become.
Can I Drive with the DPF Light On?
Even though your car won’t stop running when the DPF light comes on, continuing to drive can cause further issues.
You can expect reduced vehicle performance, decreased fuel efficiency or even engine damage if you keep driving with a blocked DPF.
Not to mention that the ECU will put your vehicle into ‘limp home’ mode if you keep driving, meaning that your car may not restart next time you turn the ignition on.
Preventative maintenance of your car's DPF can save you the stress of a vehicle breakdown in the middle of nowhere.
Will a Blocked DPF Clean Itself?
A DPF that is significantly blocked won’t clean itself through the regeneration process.
You'll have to take your car to a garage so they can do a manual – or ‘forced’ - regeneration.
If the filter needs to be replaced altogether, this can cost upwards of £1,000, plus labour.
Replacement will be necessary if your DPF is significantly blocked, as a clean won’t be effective.
That’s why it pays to be proactive and have your DPF cleaned every 6 to 9 months so that you can put off the need for a replacement as long as possible!
Remember to take your diesel car out for longer drives at higher speeds regularly so that the regeneration process has time to complete.
Want to Take Care of Your Car's DPF?
Booking a DPF clean at regular intervals is one of the best ways to keep your DPF in good condition.
When you book in for DPF cleaning through BookMyGarage, this can cost you as little as £99, and includes a full inspection, diagnosis and flush.
With all your local garage options in one place, you can compare nearby garages to book an appointment that suits your needs.
For added convenience, why not booking a mobile DPF clean? That way you can prolong your DPF’s lifespan without the hassle of getting to a garage.
A mobile mechanic can come to you at a time and place that works for you, meaning you can get a DPF clean even from the comfort of your driveway.
You can make a booking in just 3 steps and can browse and compare your options to book online for free, 24/7.
Simply enter your reg and postcode into the booking tool below to get one step closer to a clean DPF.
