Engine Series: Cummins B6.7: Found in medium-duty trucks, school buses, and yard spotters.

• Cummins L9: Found in vocational trucks (dump trucks, refuse), transit buses, and emergency vehicles.

Model Years: Typically covers engines from 2017 to 2024+ (EPA17, EPA21, and EPA24 emissions levels).

Common Vehicle Applications:

• Freightliner: M2 106, Custom Chassis (School Bus).

• International: MV Series, HV Series.

• Kenworth: T280, T380, T480.

• Peterbilt: 536, 537, 548.

• Transit/School Buses: Blue Bird, Thomas Built, New Flyer.

he Filter Core: At the center of the kit is a wall-flow substrate, usually made of cordierite or silicon carbide, featuring a honeycomb structure that traps soot while allowing exhaust gases to pass through.

Service Solution: These kits are often sold as "service kits" for when a DPF has reached its ash-loading limit and can no longer be cleaned, or if the internal substrate has cracked (melted) due to uncontrolled regeneration.

Comprehensive Hardware: To ensure a leak-free installation, the kit includes specialized high-temperature gaskets and V-band clamps. These are critical because even a small exhaust leak before or at the DPF can cause sensor errors and prevent the "Regen" process.

Emissions Compliance: Using the correct kit for L9 or B6.7 engines is vital for maintaining the vehicle's legal emissions status and avoiding "Derate" modes where the engine's power is restricted by the computer.

Frequent or "Incomplete" Regenerations: If the vehicle requests a parked regeneration much more often than usual (e.g., every few hours instead of every few days), the filter may be "ash-loaded." Ash cannot be burned off and requires professional cleaning or replacement.

Engine Derate (Power Loss): The Engine Control Module (ECM) monitors the pressure difference across the DPF. If the filter is too restricted, the engine will enter "Derate" mode, significantly limiting speed and torque to protect the engine.

Black Smoke from Tailpipe: A healthy DPF should trap 99% of soot. If you see black smoke or notice heavy soot buildup inside the exhaust tip, the ceramic substrate inside the DPF is likely cracked or "melted."

Fault Codes (DTCs):

• Code 1921/1922: DPF Differential Pressure - Data Valid But Above Normal Operating Range.

• Code 3167: Aftertreatment DPF Regeneration - Sustained Low Temperature.

Visible Cracks or "Face Plugging": Upon physical inspection, if the inlet face of the filter is covered in a thick, hard layer of soot (face plugging) or shows orange/red discoloration, the kit needs replacement.

Internal Rattling: If you remove the DPF and hear a rattling sound when shaking it, the internal brick has broken loose from its matting.