SPN 157 FMI 1 is a Detroit™ high-pressure fuel diagnostic fault code, and this 2-page Detroit DD Series PDF documents the “Fault of the Fuel Rail Pressure Sensor, Wiring, or Quantity Control Valve” condition in full. The MCM sets this code when fuel rail pressure runs 200 bar higher than requested for eight seconds. Listed causes are a faulty fuel rail pressure sensor, a faulty Quantity Control Valve, a faulty MCM or faulty wiring. The summary below sets out the official causes, tools and troubleshooting order so a technician can verify the code before downloading the complete manual.
Official document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Publication no. | Not printed on sheet (Detroit™ via TruckFaultCodes.com, © 2017) |
| Year / Revision | 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
SPN 157 FMI 1 document contents
- Fault code identification (SPN and FMI)
- Fault description and possible causes
- Multiple-code check
- Fuel rail pressure sensor verification
- Fuel System Integrity Check test
- Actual vs desired rail-pressure comparison
Applicable truck models
This procedure applies to Detroit DD Series diesel engines on the EPA07 emissions platform. Diagnosis uses the diagnostic tool to compare actual rail pressure (ASL001) against desired rail pressure (AS098). For factory service data, wiring diagrams and bulletins beyond this fault-code sheet, consult the official Detroit Diesel support site.
Who needs this SPN 157 FMI 1 manual
Technicians facing a rail-pressure deviation on an EPA07 Detroit engine need this sheet to test the sensor and Quantity Control Valve before condemning the pump or MCM. It gives a clear order for the checks.
The routine has you service additional codes first, check actual rail pressure, remove and re-read the sensor off the rail, then run the Fuel System Integrity Check and compare actual against desired pressure to isolate the fault.
The full 2-page PDF is available in the DiagTechPro manuals library; a free account is required to download it. Every document in the library is indexed by suspect parameter number and failure mode identifier, so you can cross-reference related Detroit DD Series fault codes without leaving the page.
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