Cleaning your diesel particulate filter (DPF) regularly is paramount for proper vehicle function.

The DPF plays a significant role in diesel vehicles’ aftertreatment systems, capturing and storing soot particles to reduce exhaust emissions. 

Under normal conditions, DPFs are equipped with an automatic process, called regeneration, that burns off accumulated soot when the filter is full. However, DPFs in vehicles regularly driven at low speeds for short durations may never begin regeneration, causing a blockage in the filter. 

Keeping the DPF clean helps maintain the vehicle’s fuel efficiency and reduces the potential for engine damage. 

A clogged DPF may also affect drivability and cause the engine to overheat or be hard to start.

Here are six ways to tell if the DPF needs cleaning:

1. DPF Warning Light

A clear indication that the DPF is clogged is when the DPF warning lamp on the dashboard lights up. The general “check engine” light may also come on with some vehicles. Hooking up an OBD II reader may reveal a P242F or related trouble code.

2. Frequent Regeneration Cycles

If a diesel engine starts or undergoes regeneration more frequently than usual, it may indicate that the DPF is clogged and needs to be cleaned.

3. Increased Fuel Consumption

A clogged DPF forces the engine to work harder, which burns more fuel per mile. It’s generally less expensive to clean the DPF than it is to let a blocked DPF drive down fuel economy.

4. Loss of Power

A blocked DPF will restrict exhaust flow, which causes the engine to reduce acceleration, be less responsive, and have difficulty maintaining high speeds.

5. Limp Mode

If the DPF becomes clogged or fails to regenerate, it may trigger the vehicle to go into “limp mode” to prevent damage. While in limp mode, the vehicle’s power output is significantly reduced, its top speed is limited, auxiliary functions may be disabled, and it may be locked in a low gear.

6. Rough Idle

A clogged DPF can cause the engine to run rough or have trouble maintaining a steady idle. 

“You don’t have to be a mechanic to keep your diesel vehicle’s DPF functioning properly,” says Clay Parks, vice president of development for Rislone, an engine treatment brand. “Modern vehicles make it pretty obvious when there’s an issue, and Rislone makes it easy to fix." 

Rislone has formulated a blend of high-performance detergents and heavy-duty cleaning solvents are designed to scrub contaminants, soot, carbon build-up, and oily residue from the DPF and related parts.

DPF Cleancontains Rislone’s exclusive Diesel Regen Medic, an active DPF regeneration accelerator and cleaning fuel catalyst.