Got a Cummins ISX engine with a clogged DPF? If you’re seeing a check engine light or getting fault codes like SPN 3719 FMI 0 or SPN 3720, it may be time to perform a forced regeneration. The good news? You don’t need to take it to the dealer.

Here’s how to run a regen using your own diesel laptop.

🛠 What You’ll Need:

• A laptop diagnostic scanner kit

• RP1210 adapter (e.g., Nexiq USB-Link or Cummins Inline 6)

• Compatible software (cDiesel tech, Universal Diag included with your laptop)

🔄 Step-by-Step: Run a Forced Regen on a Cummins ISX

1. Connect your adapter to the 9-pin diagnostic port in your truck.

2. Launch your software (Insite or other compatible platform).

3. Connect to the ECM — select the active Cummins ISX engine.

4. Navigate to Aftertreatment Functions > "DPF Service"

5. Click “Start Regen” and follow on-screen instructions.

✅ Before You Start:

Make sure the following conditions are met:

• Engine is at operating temperature (above 140°F)

• Park brake is set

• Transmission is in neutral or park

• No active fault codes that block regen

🕐 How Long Does It Take?

A full regen can take 30 to 60 minutes, depending on soot level.

You’ll hear the RPM rise automatically and the exhaust get hot. Once it’s finished, the soot level should drop to normal, and your active codes may clear automatically.

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