SPN 157 FMI 18 is a Detroit™ high-pressure fuel diagnostic fault code, and this 2-page Detroit DD Series PDF documents the “Fuel Rail Pressure High” condition in full. The MCM sets this code when actual fuel rail pressure runs more than 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, with a 25 percent engine derate and MIL and CEL lamps. 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 18 document contents
- Fault code identification (SPN and FMI)
- Fault description and monitored parameters
- Multiple-code check
- Fuel rail pressure sensor verification
- Component replacement and verify repairs
Applicable truck models
This procedure applies to Detroit DD Series diesel engines on the EPA10 and GHG14 emissions platforms. Diagnosis uses the diagnostic tool to read actual fuel rail pressure with key on, engine off. 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 18 manual
Technicians facing a high-rail-pressure derate on a Detroit engine need this sheet to test the sensor and Quantity Control Valve before replacing costly fuel components. It is also useful for confirming the reaction and enabling conditions.
The routine has you service any additional codes first, check actual fuel rail pressure, then remove and re-read the rail pressure sensor off the rail to decide whether the sensor, valve, wiring or MCM is at 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.
Related manuals library
