Resolving Diesel Particulate Filter or DPF Related Problems

The Diesel Particulate Filter (DPF) is a mechanical device used to reduce black smoke emitted from a diesel engine's tailpipe. The black smoke is diesel PM and is a carcinogen.  Occasional problems may arise due to factors related to manufacturing, installation, or engine maintenance practices.  

Use the following protocol to resolve DPF related performance or reliability issues.

For Trucks & Buses (Including Drayage/Port Trucks)

Step 1:      Contact your installer. Your installer is the one who put the DPF on your vehicle.
Most problems are resolved in this manner

Step 2:      Contact the device manufacturer if the installer cannot resolve your complaint.
The manufacturer name and contact information is on the DPF label, located on the filter can or attached to the engine. A list of on-road manufacturer factory contacts can be found at

Step 3:      Contact ARB at 866-6DIESEL or
If the installer or manufacturer cannot resolve your complaint

If your complaint is not resolved by the installer or manufacturer, you may contact ARB and a staff will ask you specifics about your retrofit issue. Depending on the situation, they may send you a Retrofit Filter Complaint Form (Form ECARSD/IUVPB-100) to collect more information.  Once you fill out the form, please return it to ARB.  The form will be sent to the Retrofit Implementation Advocate (RIA) Team for further investigation. Below are examples of issues that the RIA helps resolve:
  • Excessive filter plugging and alarms are still present even with proper documented engine maintenance
    Click here for information on proper engine maintenance with DPF
  • The installer or manufacturer are non-responsive
  • A warranty issue is not resolved with the manufacturer
  • Other issues related to the operation of the retrofit filter that are not resolved by the installer or manufacturer

For Transport Refrigeration Units (TRUs or Reefers)

Contact ARB at 1-888-878-2826 or and contact your installer and/or manufacturer.

For 2007 and newer engines with factory installed DPFs or Original Equipment Manufacturer (OEM) filters

Contact ARB at (800) 242-4450 or

For more information

phone      866-6 DIESEL  (866-634-3735)
(916) 323-5526
mailing address    P.O. Box 2815
Sacramento, CA 95812