This Detroit DEF temperature drift sheet is the one-page guide for fault code SPN 4337 / FMI 2 on EPA10 engines, monitoring the DEF metering unit temperature. It lists the enabling conditions, the MIL lamp reaction and a short connector-inspection procedure.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD-Series (DD13, DD15, DD16) and Series 60 (DDEC VI) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 4337 / FMI 2 |
| Fault name | DEF metering unit temperature – drift |
| Emissions platform | EPA10 |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
| Source | TruckFaultCodes.com (© 2017); Detroit Power Service Literature |
Detroit DEF temperature drift sections covered
The single page defines when the monitor runs and reduces the repair to a connector check and a possible sensor replacement.
- Monitored parameter: DEF metering unit temperature
- Enabling conditions: metering unit on, no tank refill detected
- Dash lamp: MIL; verification by parked regeneration
- Disconnect the DEF metering unit temperature sensor
- Inspect the connector for bent, spread or corroded pins
- Repair the connector, or replace the sensor per Power Service Literature
Applicable truck models
The sheet applies to Detroit DD-Series (DD13, DD15 and DD16) and Series 60 DDEC VI engines on the EPA10 aftertreatment platform. Sensor removal follows “Removal of the Diesel Exhaust Fluid Temperature Sensor” in Detroit Power Service Literature, linked from the Detroit Diesel official website.
Who needs this DEF temperature drift manual
This DEF temperature drift manual suits any workshop clearing SPN 4337 / FMI 2, confirming whether pin damage or a failed sensor caused the drift before a parked regeneration is used to verify the fix.
The full 1-page PDF is available in the DiagTechPro manuals library; a free account is required to download. For workshop reference, Detroit documents the matching component removal and installation steps for SPN 4337 / FMI 2 in Power Service Literature, and technicians should keep the wiring pin numbers shown in this sheet on hand while testing on the bench.
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