This SPN 51 FMI 2 reference covers the Detroit DD Series intake throttle valve position deviation error, which the document lists with a MIL and CEL and a 10 percent engine derate. It is part of the DiagTechPro truck manuals library and preserves the original TruckFaultCodes.com Detroit fault-code library (Copyright 2017).
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-current) engines; the same fault-code procedure is also filed under the Detroit Series 60 (DDEC VI, EPA 2007) group. |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 51 / FMI 2 |
| Source | TruckFaultCodes.com Detroit fault-code library (Copyright 2017) |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Fault description and engine reaction
- Valve icing note
- ITV commanded-position tests
- ITV motor resistance and replacement
Diagnostic steps in the SPN 51 FMI 2 document
The document notes the code can set falsely from cold-weather valve icing, then uses the Intake Air Throttle service routine to command the ITV to 20, 50 and 90 percent, checking actual position against tolerance. The harness connector is inspected and ITV motor resistance is measured between pins 4 and 5; above 10 ohms the valve is replaced, with an MCM software note for EPA07 DD Platform engines.
The Intake throttle position deviation error condition on Detroit DD Series trucks is read and cleared with DiagnosticLink (formerly DDDL); the SPN and FMI pair identifies the exact circuit and failure mode. Confirm the code is active and capture freeze-frame data before running the pinpoint tests, then clear it and road-test the truck to verify the repair has held.
Applicable truck models and engines
This document applies to Detroit DD Series (EPA 2007-current) engines; the same fault-code procedure is also filed under the Detroit Series 60 (DDEC VI, EPA 2007) group. For factory service data, parts and warranty information, consult Detroit’s official DD engine support.
Who needs the SPN 51 FMI 2 manual
This reference helps DD Series technicians resolve a throttle deviation code while ruling out valve icing before replacing the ITV.
The complete PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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