SPN 164 FMI 4 is the Detroit DD Series diagnostic trouble code for fuel rail pressure sensor circuit failed low, and this page documents its official fuel rail pressure sensor circuit troubleshooting sheet. The three-page sheet warns that the fault may be induced by low battery voltage, lists an always-enabled monitor and a 25% derate with MIL and CEL, then walks the low-circuit checks.
SPN 164 FMI 4 document details
| Brand | Detroit |
| Model coverage | DD Series — DD13, DD15, DD16 |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| SPN | 164 |
| FMI | 4 |
| Fault | Fuel Rail Pressure Sensor Circuit Failed Low |
| Emissions / revision | EPA10, GHG14 — Copyright 2017 |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Description, low-battery note and engine derate
- Sensor disconnection and connector inspection
- Harness voltage measurement (pins 1 and 3)
- MCM 120-pin connector resistance and short checks
- Sensor or MCM replacement decision
Troubleshooting steps summarised
The fuel rail pressure sensor is disconnected and inspected, and with the ignition ON (key ON, engine OFF) the voltage between pins 1 and 3 is measured for 4.5 to 5.5 volts. The procedure checks the supply and signal wiring to pins 102, 58 and 78 of the MCM 120-pin connector, confirms resistance below 5 ohms, looks for a short between the signal and ground wires, and re-tests before replacing the sensor or the MCM.
Applicable truck models covered
It covers Detroit DD Series engines (DD13, DD15 and DD16) built to EPA10 emissions with GHG14 hardware and the MCM 120-pin harness. For engine specifications and warranty coverage, refer to the official Demand Detroit service resources. These troubleshooting steps are cross-checked with the Detroit Diesel Diagnostic Link (DDDL) and the official Demand Detroit service resources.
Who needs this SPN 164 FMI 4 guide
Technicians diagnosing a shorted-low sensor signal, a wiring short to ground, or a fault that appears with weak batteries use this sheet to confirm the cause.
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