This SPN 51 FMI 4 reference documents the Detroit DD Series intake air throttle circuit failed low fault and its Motor Control Module wiring checks. 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 4 |
| Source | TruckFaultCodes.com Detroit fault-code library (Copyright 2017) |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault description and engine reaction
- Multiple-code short and open checks
- MCM 120-pin harness measurements
- Intake throttle valve replacement
Diagnostic steps in the SPN 51 FMI 4 document
The document first cross-checks companion codes on SPN 3563 and SPN 411 to locate shorts or opens at Motor Control Module (MCM) 120-pin connector pins 58, 117 and 103. If only this code is present, the intake throttle valve and MCM 120-pin connector are disconnected and resistance is measured to ground and to pin 90 to distinguish a short, an open, or a failed valve.
The Intake air throttle circuit failed low 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 4 manual
This page is for DD Series technicians who need the MCM 120-pin pinout to trace a low intake-throttle circuit rather than swap parts blindly.
The complete PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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