The SPN 3250 FMI 20 fault code file is a Detroit EPA10 and GHG14 diagnostic sheet covering a Diesel Oxidation Catalyst (DOC) temperature drift, inlet low or outlet high on DD Series engines. Compiled by TruckFaultCodes.com (© 2017) from Detroit Power Service Literature, this 4-page PDF gives technicians the exact troubleshooting order for DTC 3250-20. It is a field reference, not a substitute for the full factory manuals.
Official document details
| Brand | Detroit (Detroit Diesel) |
|---|---|
| Model coverage | DD13, DD15, DD16 |
| System / group | DD Series (EPA 2007-Current) — DTCs |
| Diagnostic code | DTC 3250-20, emission level EPA10 and GHG14 |
| Fault name | DOC Temperature Drift |
| Pages | 4 |
| File size | 0.4 MB |
| Format | |
| Source | TruckFaultCodes.com, from Detroit Power Service Literature |
| Language | English |
SPN 3250 FMI 20 fault summary
It separates a genuine DOC temperature drift from related codes, comparing DOC inlet, DOC outlet and DPF outlet temperatures and testing both DOC temperature sensors. Every step is laid out as a Yes/No decision branch, so you can follow the same path a Detroit dealer technician would without guessing.
- Checking for related SPN 3242 and 3250 FMI 3, 4 and 8 codes
- Comparing DOC inlet, outlet and DPF outlet temperatures
- Ten-minute idle re-check
- Inspecting the DOC inlet temperature sensor pins
- Measuring DOC inlet and outlet sensor resistance
Applicable truck models and engines
This procedure applies to Detroit DD13, DD15 and DD16 engines in the DD Series (EPA 2007-Current) family. The procedure is built around the Aftertreatment Control Module (ACM). For engine specifications and dealer support, see the official Detroit engine support site.
Who needs this SPN 3250 FMI 20 manual
Fleet technicians, mobile diesel mechanics and DD Series owners diagnosing this code with a diesel diagnostic tool such as DDDL or DDRS will find the exact step order, pin numbers and pass/fail limits they need. Keep it beside the truck during the repair.
The complete 4-page PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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