This Detroit DEF quality final troubleshooting sheet documents fault code SPN 3364/FMI 1, Improper DEF Quality Final Warning, on GHG14 Detroit DD Series engines. It measures DEF concentration with a refractometer, tests the dosing unit and verifies NOx conversion during a parked regeneration. 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 | GHG14 |
| Publication no. | Detroit Power Service Literature (via TruckFaultCodes.com, © 2017) |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Detroit DEF quality final table of contents
- Fault code identification: SPN 3364, FMI 1
- Step 1: check for other related faults
- Step 2: measure DEF percentage (28-36%) with kit W060589001900
- Steps 3-6: inspect DEF lines and run a DEF Quantity Test
- Step 7: chart SCR temperatures and NOx sensors
- Step 8: parked regeneration and 85% NOx conversion check
Applicable truck models
This GHG14-tier procedure applies to Detroit DD Series diesel engines with SCR aftertreatment, covering the GHG14 dosing system doser and NOx sensors. A final-warning code signals that DEF quality must be corrected to avoid escalation. See Detroit’s official service literature portal for the authoritative Detroit repair procedures.
Who needs this Detroit DEF quality final manual
Technicians handling a final DEF quality warning on a GHG14 engine will use this sheet to test fluid and dosing quantity before replacing the doser. It suits workshops verifying repairs with a parked regeneration.
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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