This Detroit DEF final warning troubleshooting sheet documents fault code SPN 3364/FMI 1, Improper DEF Quality Final Warning, on EPA10 Detroit DD Series engines. It measures DEF concentration, compares DEF pressure to ambient, flushes the metering unit and verifies NOx conversion. Diagnosis uses a diesel diagnostic tool.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | DD Series diesel engines (DD13, DD15, DD16), EPA 2007 and newer |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 3364 / FMI 1 |
| Emission tier | EPA10 |
| Publication no. | Detroit Power Service Literature (via TruckFaultCodes.com, © 2017) |
| Pages | 4 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Detroit DEF final warning table of contents
- Fault code identification: SPN 3364, FMI 1
- Steps 1-3: measure DEF percentage (28-36%) with kit W060589001900
- Steps 4-6: compare DEF pressure to ambient air pressure
- Steps 7-8: inspect DEF lines and run a DEF Quantity Test
- Steps 9-11: flush the DEF metering unit with warm water
- Steps 12-16: chart NOx sensors and run parked regenerations
Applicable truck models
This EPA10-tier procedure applies to Detroit DD Series diesel engines with SCR aftertreatment, covering the DEF pressure sensor, metering unit dosing valve and NOx sensors. A final-warning code means engine performance is at risk if DEF quality is not corrected. See Detroit’s official service literature portal for the authoritative Detroit repair procedures.
Who needs this Detroit DEF final warning manual
Technicians facing a final DEF quality warning on an EPA10 engine will use this sheet to test fluid, pressure and NOx conversion before parts are replaced. It suits workshops that must escalate with dual regeneration log files.
The full PDF is available in the DiagTechPro manuals library — a free account is required to download. It is offered for reference alongside your Detroit diesel diagnostic tool. DiagTechPro catalogues Detroit fault-code documents so technicians can locate the exact SPN and FMI they are chasing without paging through a full engine service manual. Each entry lists the page count, file size and emission tier up front, and links to the closely related codes shown below so a diagnosis can move quickly from one fault to the next.
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