The SPN 973 FMI 2 document is a Detroit DD Series diagnostic trouble code guide covering the Evobus 5-stage retarder level position not plausible condition and its step-by-step troubleshooting. This 1 page 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 973/FMI 2 — Evobus 5-Stage Retarder Level Position Not Plausible |
| Publication no. | Not stated (TruckFaultCodes.com DTC reference) |
| Year / Revision | © 2017 |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
SPN 973 FMI 2 document sections
- Fault code identification: SPN 973/FMI 2 — Evobus 5-stage retarder level position not plausible
- Short to power / open circuit on pin 13 of the CPC4 #2 connector
- Referencing OEM literature for wiring schematic information
- Note: CPC4 digital outputs share SPNs with MCM2.1 faults; the diesel diagnostic tool distinguishes them
Applicable truck models covered
The SPN 973 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, CPC4 connector, diesel diagnostic tool and OEM literature, and works through locating the short to power or open circuit on pin 13 of the CPC4 #2 connector using OEM wiring schematics. 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 973 FMI 2 manual
This reference suits Detroit-certified technicians and fleet workshop owners diagnosing the Evobus 5-stage retarder level position not plausible 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.
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