The Detroit DEF dosing unit fault sheet is the official Detroit DD Series diagnostic for a DEF dosing shutdown before a cycle completed, stored under SPN 3361 FMI 31 for GHG14 calibrations. It records the monitored parameter DEF Dosing Unit, verification by SCR ADS Self Check, exactly as published by TruckFaultCodes.com (© 2017).
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series diesel engines (EPA 2007-current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 3361 / FMI 31 |
| Fault condition | Diesel Exhaust Fluid (DEF) Dosing Unit Error |
| Monitored parameter | DEF Dosing Unit |
| Verification | SCR ADS Self Check |
| Emissions calibration | GHG14 |
| Source / Publisher | TruckFaultCodes.com |
| Year / Revision | 2017 |
| Pages | 2 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification: SPN 3361, FMI 31
- Description and monitored parameter
- Typical enabling conditions
- Troubleshooting steps
- Component inspection and repair verification
Detroit DEF dosing unit troubleshooting steps
The sheet has the technician clear any other DEF system circuit faults (FMI 3, 4 or 5) first, inspect the dosing-unit harness and connector, then run the SCR Airless Dosing System (SCR ADS) Self Check and confirm DEF pump speed of 750-1800 rpm and DEF pressure of 130-160 psi, replacing the metering/dosing unit if the routine fails.
Applicable truck models
This code sheet applies to trucks powered by Detroit DD Series diesel engines built to the GHG14 emissions calibration; always match the SPN 3361 FMI 31 listing to the vehicle’s own engine family before repair. Confirm the emissions family on the vehicle emissions label, because aftertreatment and dosing hardware differs between the EPA07, EPA10 and GHG14 builds and a mismatched procedure can send you to the wrong component. For engine coverage and dealer service information, see the Detroit Diesel official website.
Who needs this Detroit DEF dosing unit manual
Fleet technicians and independent workshops that service Detroit DD Series engines use this Detroit DEF dosing unit reference to confirm the code, its enabling conditions and the correct repair before replacing parts. It is written for the mechanic making the repair decision, not the driver, and pairs with the wiring diagrams and component removal procedures Detroit publishes in Power Service Literature.
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