This SPN 51 FMI 18 reference covers the Detroit DD Series intake throttle valve position data that is valid but below the normal operating range at a moderately severe level. 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 18 |
| 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 enabling conditions
- Valve icing note
- ITV commanded-position tests
- ITV motor resistance and replacement
Diagnostic steps in the SPN 51 FMI 18 document
The document flags possible cold-weather valve icing, then commands the Intake Throttle Valve to 20, 50 and 90 percent and confirms the actual position stays within tolerance. Where it fails, the harness connector is inspected for damage and ITV motor resistance is measured between pins 4 and 5; above 10 ohms the valve is replaced, and cold-temperature data is reviewed before releasing the vehicle.
The Intake throttle position data valid but below normal operating range – moderately severe level 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 18 manual
It is aimed at DD Series technicians confirming whether a below-range throttle reading is a real actuator fault or cold-weather icing.
The complete PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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