If your diesel truck shows high soot, poor performance, or DPF/aftertreatment warnings, you may need to run a forced regeneration. A forced regen manually commands the ECM to burn soot out of the Diesel Particulate Filter (DPF) when normal driving or parked regen cannot complete it.
This guide shows step-by-step how to perform a forced regeneration on all major engines, including Cummins, Detroit Diesel, CAT, Paccar, Volvo, Mack, International/MaxxForce, Hino, Isuzu and more.
What Is a Forced Regen?
A forced regeneration is a computer-initiated cleaning cycle that uses high exhaust temperatures to burn soot out of the DPF. Unlike passive or active regen, a forced regen is initiated with a diagnostic laptop when the filter is too clogged for normal methods.
When a Forced Regen Is Needed
You should run a forced regen when:
- DPF light stays on
- Regen light flashes or requests manual regen
- Soot level too high for automatic regen
- The truck enters power reduction or derate mode
- Recent regens failed to complete
- You replaced DPF components and need to reset values
Requirements Before Starting a Forced Regen
- Key ON, engine OFF (unless software requires engine idle)
- Parking brake engaged
- Transmission in park or neutral
- Coolant temp usually above 160°F
- No safety-related active codes
- Exhaust area clear of people and objects
Some faults can prevent regen from starting until corrected.
Tools You’ll Need
- Diesel diagnostic laptop or scan tool
- RP1210-compliant or OEM adapter (Nexiq USB-Link 3 recommended)
- The correct software for your engine
Best Diagnostic Programs for Forced Regen
- Cummins: INSITE
- Detroit Diesel: DDDL
- CAT: CAT ET
- Paccar: ESA
- Volvo/Mack: Tech Tool (VOCOM adapter required)
- International/MaxxForce: ServiceMaxx or NED
- Isuzu: IDSS
- Hino: Hino DX
If you are unsure which program to use, Diesel Tech or Universal Diag is the fastest all-in-one solution.
How to Force Regen (All Engines – Step-by-Step)
Step 1: Connect to the Truck
- Plug the diagnostic adapter into the vehicle’s 9-pin/16-pin port.
- Connect the adapter to your laptop.
- Turn the key to ON (engine OFF or idle depending on software).
- Open the correct diagnostic program.
Step 2: Identify the Vehicle
- Select the engine make and model
- Verify VIN and ECM type
Step 3: Check for Fault Codes
Before forcing regen, view active and inactive codes. The following faults often block regeneration:
- DPF pressure sensor faults
- EGR flow or valve errors
- NOx sensor failures
- DEF quality/dosing faults
- Temperature sensor faults
Clear or repair any blocking faults before continuing.
Step 4: Navigate to the Regeneration Menu
Look for options such as:
- Aftertreatment
- DPF Service
- Maintenance Routines
- Forced Regeneration
Step 5: Start the Forced Regen
- Select Start Regen, Manual Regen, or Forced Regen.
- Follow on-screen prompts.
- Engine RPM may rise between 1,000–1,500 RPM.
- Exhaust temperatures increase to 1,000–1,300°F.
A typical forced regen lasts 20–45 minutes.
Step 6: Monitor Live Data
- Soot percentage
- DPF differential pressure
- Exhaust gas temperatures
- Fuel injection changes
- Regen status (active/in-progress)
Soot levels should drop steadily during regen.
Step 7: Verify Completion
After regen finishes, confirm:
- Soot level is within normal range
- DPF pressure is low at idle
- No active aftertreatment faults remain
- Regen history shows “Completed”
Engine-Specific Forced Regen Notes
Cummins
- Use INSITE > ECM Diagnostic Tests > Aftertreatment > Force Regen
- Cummins often requires coolant above 160–180°F
Detroit Diesel
- DDDL > Aftertreatment > DPF Service > Perform Regen
- Look for SPN 3719, 4364, and 5246 (common blockers)
CAT
- CAT ET > Service > Aftertreatment Regeneration
- Make sure no DOC/DPF temp sensor codes are active
Paccar
- ESA > Maintenance > Aftertreatment System > DPF Regen
Volvo / Mack
- Tech Tool > Operations > Parked Regen
- Requires VOCOM adapter
When a Forced Regen Will NOT Fix the Problem
A forced regen will not resolve issues caused by:
- Cracked or melted DPF
- Low DEF quality or clogged DEF doser
- NOx sensors out of range
- Severe EGR system restrictions
- Turbo, dosing, or fueling problems
In these cases, diagnostics or component replacement is required.
Need Help?
If you’re having trouble getting a forced regen to start, or don’t know which software to use, contact our support team below:
- Phone (Toll Free): (877) 210-3245
- Email: info@truckscanners.com
- Contact Page: https://truckscanners.com/contact/
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