SPN 2631 FMI 3 is the Detroit DD-Series diagnostic fault code document for the intake manifold pressure sensor circuit failed high event, published on TruckFaultCodes.com (copyright 2017) and archived as a 2-page PDF in the DiagTechPro library. The document covers a failed-high circuit on the intake manifold pressure/temperature sensor, with voltage checks routed back to the Motor Control Module (MCM) 120-pin connector.
SPN 2631 FMI 3 document details
| Brand | Detroit |
| Model coverage | Detroit DD-Series (DD13, DD15 and DD16), EPA 2007 and later |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| Fault code (SPN) | 2631 |
| Failure mode (FMI) | 3 |
| Emissions calibration | All model years |
| Source | TruckFaultCodes.com (copyright 2017) |
| Pages | 2 |
| File size | 0.22 MB |
| Format | |
| Language | English |
The page records the official identifiers so a technician can confirm the exact code and calibration against the diesel diagnostic tool before starting any repair.
Document table of contents
- Fault code identification (SPN 2631 / FMI 3)
- Circuit failed high description
- Step 1 – Check for multiple codes
- Steps 2 to 4 – Sensor and harness inspection
- Steps 5 to 7 – Voltage measurements at the MCM
- Intake pressure/temperature sensor removal reference
The procedure first checks whether related codes are present, then disconnects the intake manifold pressure/temperature sensor and inspects the harness for bent, spread or corroded pins. With the ignition on, voltage is measured between pins 2 and 4 and between pins 1 and 4 on the harness side of the sensor, comparing each reading against a 4.5-volt threshold. Depending on the result, the technician either repairs the wire to pin 87, pin 58 or pin 102 of the MCM 120-pin connector, or replaces the sensor using the referenced removal routine.
Applicable truck models
This document applies to Detroit DD-Series diesel engines in the EPA 2007-and-later range, typically the DD13, DD15 and DD16 as covered by the All model years calibration shown on the file. Confirm the engine calibration and connector layout for your chassis on the official Detroit engine site before ordering parts.
Who needs this SPN 2631 FMI 3 manual
Mechanics diagnosing boost or intake-air readings on a Detroit DD-Series engine will use this page to test the pressure/temperature sensor wiring before condemning the sensor itself.
The complete 2-page PDF is available in the DiagTechPro manuals library, where a free account is required to download it.
Related manuals library
