SPN 4375 FMI 3 is the Detroit Diesel diagnostic trouble code set when a Diesel Exhaust Fluid (DEF) Pump Circuit Failed High condition is detected on DD Series (EPA 2007-current) engines. This 2-page troubleshooting sheet lists the fault definition, the relevant monitor or note data, and a numbered diagnostic routine that ends in the correct wiring or component repair. It is drawn from TruckFaultCodes.com (© 2017) and applies to the GHG14 emissions calibration.
Official document details
| Brand | Detroit Diesel |
|---|---|
| Model coverage | DD Series engines (EPA 2007-current) |
| System / group | DTCs — DEF pump circuit |
| Suspect parameter (SPN) | SPN 4375 |
| Failure mode (FMI) | DEF pump circuit failed high |
| Emissions calibration | GHG14 |
| Dash lamps | MIL, CEL |
| Engine reaction | 25% derate |
| Verification | SCR ADS self-check |
| Source / copyright | TruckFaultCodes.com, © 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format / language | PDF / English |
SPN 4375 FMI 3 table of contents
The routine opens with the diesel diagnostic tool connected and the key ON (engine off), then runs the Selective Catalytic Reduction Airless Dosing System (SCR ADS) self-check to see whether the fault is active. If it stays active, the DEF pump four-pin connector is unplugged and inspected for bent, spread or corroded pins. When the pins are sound, the sheet directs a repair of the short-to-battery (12 volts) between pin 3 of the DEF pump connector and pin 20 of the ACM2.1 120-pin connector.
- Fault code header and copyright
- Description: monitored parameter and enabling conditions
- Troubleshooting steps 1 to 6
- DEF pump four-pin connector pin-out (RPM feedback, supply, RPM control, ground)
- Short-to-battery repair and code clearing
Applicable truck models
This sheet is part of the DD Series diagnostic trouble code library and addresses the DEF pump electrical circuit that feeds the SCR airless dosing system. The SPN 4375 FMI 3 procedure applies to Detroit DD Series (EPA 2007-current) engines running the GHG14 calibration, and the same code index is cross-referenced under the Detroit Series 60 (DDEC VI, EPA 2007) fault-code set. For engine identification and warranty details, see the Detroit Diesel official site.
Who needs this SPN 4375 FMI 3 manual
This sheet is written for diesel technicians and workshop owners diagnosing a DEF pump derate on Detroit DD Series trucks. It gives the exact connector pin map needed to isolate a high circuit fault without guesswork.
The full 2-page PDF is available in the DiagTechPro manuals library; a free account is required to download.
Related manuals library
