SPN 164 FMI 21 is the Detroit DD Series diagnostic trouble code for rail pressure sensor drift low, and this page documents its official fuel rail pressure sensor circuit troubleshooting sheet. The three-page sheet lists the monitored parameter, enabling conditions and a 25% engine derate with MIL and CEL, then walks the fuel rail pressure sensor and Motor Control Module (MCM) wiring checks.
SPN 164 FMI 21 document details
| Brand | Detroit |
| Model coverage | DD Series — DD13, DD15, DD16 |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| SPN | 164 |
| FMI | 21 |
| Fault | Rail Pressure Sensor Drift Low |
| Emissions / revision | EPA10, GHG14 — Copyright 2017 |
| Pages | 3 |
| File size | 0.4 MB |
| Format | |
| Language | English |
Document table of contents
- Description, dash lamps and engine derate
- Fuel rail pressure sensor disconnection and inspection
- Harness voltage measurement (pins 1 and 3)
- MCM 120-pin connector resistance checks
- Sensor or Motor Control Module replacement decision
Troubleshooting steps summarised
With the fuel rail pressure sensor disconnected and the connector inspected for damage, the technician turns the ignition ON (key ON, engine OFF) and measures the voltage between pins 1 and 3 of the harness connector, expecting 4.5 to 5.5 volts. Follow-on steps check the supply and signal wires to pins 102, 58 and 78 of the MCM 120-pin connector, measure circuit resistance below 5 ohms, verify the signal-to-supply resistance above 10K ohms, then re-test before replacing the sensor or the MCM. If the fault is still unresolved after the wiring is confirmed, the sheet directs the technician to contact the Detroit Customer Support Center at 800-445-1980.
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 fuel-system 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 21 guide
Technicians facing a slowly drifting low rail-pressure signal, a 25% derate, or a suspect sensor supply on the fuel system use this sheet to isolate wiring from sensor faults.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download the complete step-by-step document.
Related manuals library
Sản phẩm liên quan cho hãng này
Cùng brand theo taxonomy hiện có trong catalog WooCommerce.
Detroit Diesel Reports 6.3
Detroit Reprogramming Station (DDRS) 7.11
DDDL Backdoor Password: A Comprehensive Guide
