The SPN 972 FMI 2 document is a Detroit DD Series diagnostic trouble code guide covering the throttle inhibit switch signal not plausible due to excess vehicle speed condition and its step-by-step troubleshooting. This 2 pages PDF is compiled from the TruckFaultCodes.com Detroit fault codes reference (© 2017) for the DD Series (EPA 2007-Current) / DTCs set. It is written for workshop diagnostics rather than general reading.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD Series (EPA 2007-Current) engines |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Diagnostic trouble code | SPN 972/FMI 2 — Throttle Inhibit Switch Signal Not Plausible |
| Publication no. | Not stated (TruckFaultCodes.com DTC reference) |
| Year / Revision | © 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
SPN 972 FMI 2 document sections
- Fault code identification: SPN 972/FMI 2 — throttle inhibit switch signal not plausible due to excess vehicle speed
- Checking for multiple codes: CPC4 SPN 168/FMI 0/14/18 battery voltage faults
- Checking for MCM2.1 SPN 625/FMI 9 CAN line faults
- Verifying CPC4 configuration and retesting the active fault
- Inspecting the throttle inhibit switch harness and repairing CPC4 connector #1 pin 9
Applicable truck models covered
The SPN 972 FMI 2 fault applies to trucks fitted with Detroit DD Series (EPA 2007-Current) engines and the associated Common Powertrain Controller and Motor Control Module modules, covering GHG14 calibrations. The procedure references Common Powertrain Controller, throttle inhibit switch, Motor Control Module and CPC4 connector, and works through checking related battery-voltage and CAN codes, inspecting the switch harness, then repairing CPC4 connector #1 pin 9. Confirm the engine and emissions configuration against the vehicle build before ordering parts; verify current procedures on the Detroit Diesel official site.
Who needs this SPN 972 FMI 2 manual
This reference suits Detroit-certified technicians and fleet workshop owners diagnosing the throttle inhibit switch signal not plausible due to excess vehicle speed condition on DD Series engines. Every troubleshooting step and decision branch from the original PDF is preserved so the on-vehicle diagnosis can be followed in sequence, and the document names the exact connectors, pins and modules involved. Use it alongside a Detroit-compatible scan tool such as DDDL or DDRS.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download.
Related manuals library
