This HC doser supply pressure sheet documents Detroit SPN 3480 FMI 16, set when the cutoff is commanded to 100 percent yet compensation pressure stays above 95 psi. It builds from fault triage to a measured priming-port test. Follow the steps to confirm the control valve.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | DD Series (EPA 2007-Current); also filed under Series 60 (DDEC VI – EPA 2007) |
| System / Group | DTCs — High Hydrocarbon (HC) Doser Supply Pressure High |
| Fault code | SPN 3480 / FMI 16 |
| Source | www.TruckFaultCodes.com (© 2017) |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
HC doser supply pressure diagnostic guide
After safing the vehicle, the technician confirms SPN 3480 FMI 14 is not active and repairs any fuel system faults first. Using tool J-48876, priming port pressure is measured at 70 to 90 psi at 600 rpm idle and 100 to 140 psi at 1800 rpm. Pressures within range point to the doser pressure control valve in the high pressure flange; out-of-range pressures send the technician to the low pressure fuel system measurement procedure. A high idle regeneration and the retained log finish the job when the support centre is involved.
Document table of contents
- Fault code identification: SPN 3480, FMI 16
- Fault condition: cutoff at 100 percent, pressure above 95 psi
- Fuel-fault and SPN 3480 FMI 14 checks
- Priming-port pressure test with tool J-48876
- High idle regeneration and verification
Applicable truck models
This procedure applies to Detroit DD Series engines built for EPA 2007 and later, covering all model years (EPA07, EPA10 and GHG14) as printed on the document cover, and the identical SPN/FMI sheet is also filed under Detroit Series 60 (DDEC VI, EPA 2007). Confirm the emissions platform on your truck and cross-check the connector and pin numbers against the official Detroit engine support site before making any repair.
Who needs this HC doser supply pressure manual
A diesel technician on any Detroit DD model year with a high supply pressure complaint uses this sheet to measure the priming port properly and decide on the control valve rather than guessing.
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