This Detroit improper DEF quality troubleshooting sheet documents fault code SPN 3364/FMI 2 on EPA10 Detroit DD Series engines, where the monitored parameter is DEF quality after a refill event. It measures fluid 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 2 |
| Emission tier | EPA10 |
| Publication no. | Detroit Power Service Literature (via TruckFaultCodes.com, © 2017) |
| Pages | 4 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Detroit improper DEF quality table of contents
- Fault code identification: SPN 3364, FMI 2
- Description: DEF quality after a refill event, MIL/CEL lamps
- Steps 3-6: measure DEF percentage and DEF pressure vs ambient
- 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. The 70% NOx conversion threshold guides the repair decision. See Detroit’s official service literature portal for the authoritative Detroit repair procedures.
Who needs this Detroit improper DEF quality manual
Technicians who read this DEF quality code after a refill will use the sheet to test fluid, pressure and NOx conversion before condemning the metering unit. It suits workshops documenting the required dual regenerations.
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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