Why does my truck keep saying cleaning the exhaust filter?
It's telling you the diesel particulate filter is regenerating to burn off soot; this is normal when the filter is loaded, but persistent messages can indicate a problem with the system or driving pattern that prevents a complete regeneration.
Diesel trucks are equipped with a exhaust aftertreatment system designed to reduce emissions. Central to this system is the diesel particulate filter (DPF), which traps soot. When the filter fills, the engine management system starts a regeneration—either automatically during normal highway driving (passive regen) or through an active regeneration that raises exhaust temperatures to burn off the soot. If you keep seeing the “cleaning the exhaust filter” alert, your vehicle is trying to clear the filter, but something may be preventing it from finishing the process.
What the message means
The dashboard alert indicates the vehicle is initiating or is in the middle of a regeneration cycle for the DPF. A successful regeneration clears most of the soot, allowing the filter to continue trapping particles. If the cycle doesn’t complete, or if the alert comes back repeatedly, it can mean the filter is becoming clogged, the sensors aren’t reading correctly, or there are other exhaust or engine issues to address.
How a DPF regeneration works
Most modern trucks use two regeneration modes. Passive regen happens during regular highway driving when exhaust temperatures are high enough to burn soot automatically. Active regen is initiated by the engine control unit (ECU) when soot levels get too high, temporarily increasing exhaust temperatures (and sometimes fuel use) to burn off more soot. Both processes aim to keep soot from plugging the filter, but they rely on driving conditions and sensor information to function correctly.
Common causes
Before you act, it helps to know why the message might keep appearing. Below are the typical factors that keep a DPF regen from completing or trigger frequent regenerations.
- Short trips and lots of idling, which prevent the exhaust from reaching the temperatures needed for effective regeneration.
- Frequent stop-and-go driving or heavy towing, which increases soot production and can overwhelm the regeneration cycle.
- Faulty or dirty sensors, such as the differential pressure sensor, temperature sensors, or oxygen sensors, that misreport the filter’s load.
- Exhaust leaks or a restricted exhaust path that impede proper regeneration temperatures.
- Ash buildup in the DPF (as opposed to soot); ash cannot be burned off during regen and may require professional cleaning or replacement.
Understanding these causes helps you decide whether the issue is a routine maintenance need or a sign of a more serious fault.
What to do now
If you’re facing a recurring “cleaning the exhaust filter” message, the following steps can help address the issue or prevent it in the future.
- Drive at highway speeds for 20–40 miles (30–60 minutes) to allow a passive or active regeneration to complete. Plan longer trips when possible to give the system a chance to finish.
- Check for dashboard warning lights or codes with a compatible OBD-II scanner. Look specifically for DPF-related codes and note any sensor or exhaust faults.
- Inspect basic maintenance items: fuel quality, fuel system health, engine oil level and grade, and ensure there are no obvious exhaust leaks or damaged components.
- If the message persists after a proper highway drive, have a professional diagnosis performed. A technician can confirm DPF loading, check sensors, perform a forced regeneration if needed, and inspect EGR and turbo systems.
- Consider DPF cleaning or, if necessary, DPF replacement or ash cleaning. Some vehicles require professional cleaning to remove ash buildup that cannot be burned off during regen.
Persistent warnings can indicate a fault that, if ignored, may lead to reduced engine performance, low fuel efficiency, or the vehicle entering a safety limp mode. When in doubt, seek certified service.
Summary
The message about “cleaning the exhaust filter” is tied to the diesel particulate filter’s regeneration process. It’s usually normal during periods of soot buildup, but repeated or unresolved regenerations suggest driving patterns, sensor faults, or exhaust system issues that need attention. Start with longer drives to complete regenerations, check for codes, and consult a professional if the warning continues. Regular maintenance and mindful driving can help prevent premature DPF problems and keep your truck compliant with emissions requirements.
What does cleaning an exhaust filter keep driving mean?
“CLEAN EXHAUST FILTER SEE OWNERS MANUAL NOW” or “CLEANING EXHAUST FILTER KEEP DRIVING UNTIL MESSAGE IS. CLEARED” If either of the messages appear on the driver information center (DIC) then a DPF cleaning (regeneration) is required.
How long do you have to continue driving to clean an exhaust filter?
You should continue driving for at least 10-15 minutes at highway speeds to let the exhaust filter (DPF) clean itself. For a more thorough clean, drive for 30 minutes or more at a steady speed of over 30-40 mph. It's crucial to drive and avoid idling, as this can prevent the self-cleaning process from completing, according to this YouTube video and the NHTSA.
This video explains how to regenerate a DPF: 59sMyks GarageYouTube · Jul 18, 2022
Driving instructions
- Start driving immediately: and avoid idling.
- Maintain a steady speed: of over 30-40 mph.
- Drive for at least 10-15 minutes: to start the cleaning cycle.
- Drive for 30-50 minutes: for a more complete regeneration.
- Listen for signs of regeneration, such as increased fan noise or a change in engine sound, as explained by FleetPrices.co.uk.
- Monitor the dashboard: and continue driving until the warning light goes off.
Important considerations
- Regularly ignore short trips: that don't allow the DPF to reach a high enough temperature to clean itself. This can lead to more serious issues.
- Consult your owner's manual: for the most accurate information specific to your vehicle.
- If the light remains on: after driving for an extended period, it's best to seek professional help, as the filter may be too clogged.
Why does my truck say cleaning the exhaust filter?
The exhaust filter cleaning light indicates active Diesel Particulate Filter (DPF) regeneration to burn off soot. This process typically starts after driving 5-10 miles at highway speeds. If the light stays on too long or returns frequently, check for clogged DPF, faulty temperature sensors, or exhaust leaks.
What happens if you don't clean your exhaust filter?
And What Happens if You Don't Clean Your DPF? The more soot and ash that is clogged in your DPF, the more black exhaust fumes you'll see coming off your vehicle as you drive, as well as an increase in pressure on your exhaust.
