Hydrocarbon Doser Fuel Line Pressure Low SPN 3480/FMI 2

Description Hydrocarbon (HC) Doser Fuel Line Pressure Low

Monitored Parameter HC Doser Fuel Line Pressure

Typical Enabling Conditions Dosing Enabled

Execution Frequency Continuous When Enabling Conditions Met

Typical Duration One Minute

Dash Lamps MIL, CEL

Engine Reaction Derate 10%

Verification Parked Regeneration


  1. Are there any fuel system faults present?
    1.     Yes; repair fault with the highest priority listed below. Verify repair. 3480/3, or 4 4077/3, or 4 3480/1, 4077/14
    2. No; Go to step 4.
  2. Start the engine.
  3. Using DiagnosticLink, perform two back-to-back “Purge Hydrocarbon Doser” service routines to help improve the chances of identifying a leak.
  4. Turn the ignition OFF.
  5. Visually inspect the fuel line between the HC doser block assembly and fuel doser injector valve for any sign of external fuel leaks. Are any external leaks present?
    1. 1. Yes; replace the HC doser injector valve fuel supply line. Go to step 8.
    2. No; replace the HC fuel doser injector valve. Refer to section “Removal of the Hydrocarbon Doser Fuel Injector Valve” . Go to step 8.
  6. Turn the ignition ON and start the engine.
  7. Clear fault codes.
  8. Perform a parked regeneration to verify the repair. Did SPN 3480/FMI 2 become active during regeneration?
    1.      Yes; replace doser block. Refer to section “Removal of the Hydrocarbon Doser Fuel Injector Valve” . Verify repair.
    2.    No; release vehicle.

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